JPS6338194Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jam detection device for moving members such as copying materials and copying materials.

In a copying machine that automatically feeds copy materials such as sheet originals and photosensitive paper to process a large number of sheets without much effort, the sheet original or photosensitive paper may jam due to paper jams in the moving path. This will reduce the efficiency of the autofeed and endanger the safety of the equipment.

Traditionally, paper jam detection in copying machines was carried out using
As seen in Publication No. 8436, the leading edge of the paper is detected by a paper detection means installed at the entrance of the transfer path, and a timer that sets the standard time to the exit is activated, and the paper is delivered to the exit within that time. There is something that stops the fuser when the leading edge does not reach it.

However, in this jam detection, the timer is activated in response to the detection of the leading edge of the paper, so it is necessary to set the time required for the entire travel of the moving path using the timer. Therefore, in a copying machine or the like that has a long moving path and performs intermediate exposure or fixing, a very long timer is required. In other words, if the timer is configured with a simple charging/discharging circuit, the long-term setting accuracy will be low, so if the timer is activated by detecting the leading edge of the paper as described above, it is necessary to detect the leading edge of the paper and operate the timer. In the case of continuous autofeed in which the next sheet is fed, there is a drawback that it is not possible to continuously detect jams in subsequent sheets.

Furthermore, if the paper has a hole for a file, when the paper moves over the paper detector and moves from a non-hole area to a hole area, or from a hole area to a non-hole area, the paper detector will detect the rear edge of each paper. Outputs false signals for passage and tip passage. Therefore, this erroneous signal may cause a malfunction in jam detection.

Another conventional example, as disclosed in Japanese Patent Publication No. 44-8433, detects a jam based on the operational relationship between a switch based on one rotation of the copying drum and a paper detection switch at the exit, in which the moving path length is limited to one rotation of the drum. It has some drawbacks.

The present invention eliminates the above-mentioned drawbacks, and includes: a first sheet detection means provided on the sheet movement path; a second sheet detection means provided downstream of the sheet conveyance with respect to the first detection means; a timer means for performing a time-limiting operation for the time required for the leading edge of the same sheet to reach the second sheet detecting means after the trailing edge of the sheet has completed passing over the first sheet detecting means; means for detecting that the trailing edge of the sheet has completed passing over the means and starting a timed operation of the timer means; jam warning means for outputting a jam signal when the timed operation of the timer means is completed;
The apparatus further includes means for not starting the timed operation of the timer means for a predetermined period of time corresponding to the file hole after the first detection means performs the detection operation. Thereby, the time limit operation of the timer for jam detection can be made extremely short. Moreover, it is possible to feed the next moving material before the previously fed moving material reaches the exit of the moving time, it is possible to detect jams in each moving material that is continuously fed, and even if there is a hole for a file in the sheet. Highly accurate jam detection is possible without malfunction.

FIG. 1 is a block diagram showing an example in which the present invention is applied to the feeding of copy materials, in _{which S1} is a first detection means provided at the entrance of the moving path to detect copy materials (hereinafter referred to as sheets); I is an integration circuit that removes the trailing edge error signal from the first detection means, _T1 is a first timer that starts timed operation in response to the sheet trailing edge signal, and _S2 is a circuit installed near the exit of the moving path to detect the sheet. _T2 is a second timer that starts timed operation in response to the sheet _leading edge signal from _the second detection means _S2 ; D2 is a first determining means that produces an output when the second detecting means S2 does not detect the leading edge of the sheet, and _D2 is a first determining means that _produces an output when the _second detecting means _S2 does not detect the leading edge of the sheet. A second discriminator that produces an output when no detection is detected; G is a means that generates a jam signal based on the output of the first or second discriminator; Y is a drive source or sheet (sheet to be fixed) that feeds the sheet based on the jam signal; Means for cutting off the fixing heater, X
is a means for counting sheets or stopping the sheet for exposure preparation in response to a sheet leading edge signal from the first detecting means _S1 . Here, the first timer is set to the time required for the sheet to reach the second detection means after detecting the trailing edge of the sheet. Therefore, the first timer time can be shortened. Further, the second timer is set to the time required for the sheet to pass through the second detection means. Therefore, it is possible to monitor the sheet throughout the entire system and determine whether feeding has been completed. As soon as the sheet is fed and passes through the first detection means _S1 , the first timer _T1
When the second detection means _S2 is reached, the timer is activated.
Since _T1 is released, no jam signal is generated, and the second timer is activated upon arrival, and when the sheet passes normally through the second detection means _S2 , timer _T2 is released, so no jam signal is generated. If a jam occurs, a jam signal is issued by one of the timer outputs, and the sheet feeding means is stopped and subsequent sheets are stopped to prevent damage to important documents, or a warning lamp is activated. Ensure equipment safety.

This example is based on Japanese Patent Application Laid-Open No. 49-1234, which detects the leading edge of a sheet document fed to an exposure unit, stops the sheet once, and starts feeding again when the drum reaches a predetermined position, and exposes the sheet. This effect is particularly effective in electrophotographic copying apparatuses that eject paper.

Incidentally, the timer can also be used to set the time after the trailing edge is detected using a copying drum or the like based on the rotation length of the copying drum.

Further, the present invention will be explained below using, as an example, a copying machine that continuously copies a large number of stacked original sheets by continuous autofeed as shown in FIG.

The purpose of this copying machine is to provide a copying machine that can copy sheet originals with the highest efficiency. Conventionally, copying machines can be roughly divided into two types: sheet original copying machines and copying machines capable of copying three-dimensional objects such as books.

Copying machines for sheet originals that have an exposure section for transporting sheet originals cannot copy thick originals such as books, but copies can be obtained by simply feeding the sheet original into the insertion slot of the exposure section that exposes the sheet original. be able to.

Furthermore, compared to a thick document copying machine which has a document table for placing a thick document, it is possible to increase the copying speed because there is no backward stroke for the document table or optical system for the same process configuration. However, there is a limit to the speed at which the user can feed originals one by one into the insertion slot, so as the performance of machines improves, it is not possible to keep up with the speeds that machines are capable of, and the speed that the copying material itself is originally capable of is limited. I was unable to perform effectively. Furthermore, when copying an original consisting of several pages, the exposed original was reversed from the original page order, requiring the user to rearrange the order, resulting in a corresponding loss of time.

The present invention is an improvement on the above points, and includes a separation paper feeding unit that automatically and reliably feeds sheet originals one by one to the conveying exposure unit one by one, and a U-turn stacking of exposed sheet originals. It is possible to load each or both of the discharge section and the discharge section for organizing the stacked pages in the order of the stacked pages, so that even if they are loaded individually, they can perform their respective functions.

Therefore, speed insertion of a sheet original becomes possible, and at the same time, the page order of the original is automatically arranged. This embodiment is a sheet document/book document copying machine in which a sheet document feed section is combined with a document separation/feed section and a discharge section.

The operation will be explained with reference to FIG.

A plurality of sheet originals 1 are placed with the side to be copied facing down, in page order from the bottom, and placed on a stacking table 23 with the last page on top. Separation roller 7 and feed roller 6 rotating in opposite directions
As a result, the top of the stacked original sheets, that is, the last page of the original, is separated and conveyed, and is continuously passed through the pull-out roller 8 and sent between the conveyance rollers 9 built in the document table 91, and then sent to the lamp 21. The leading edge of the sheet document is detected by the light-receiving element 22 and the document is temporarily stopped. When the photosensitive drum 24 rotates to a predetermined position, the sheet original is again conveyed between the guide glass 16 and the guide plate 17 by the conveyance rollers 9 and 10 in synchronization with the drum 24, and the slit-exposed sheet original is conveyed by the ejection roller. 11,1
2 and is discharged onto the document tray 92 while making a U-turn. The conveyance speed of the pull-out roller 8 is higher than that of the feed roller 6, and the trailing edge of the first sheet document 1' and the second document are continuously and reliably separated and fed by the separation/feed roller. Between the tip and
Create a gap. This gap distinguishes the second document from the first document, and in the same way, it is temporarily stopped and controlled in conjunction with the photosensitive drum 24. When the sheet original passes over the glass plate 16 of the illumination section 25, it is irradiated by a lamp 26, and an image of the original is formed on the photosensitive drum 24 at the exposure section 29 by a reflecting mirror 27 and a mirror lens 28. The photosensitive drum 24 rotates in the direction of the arrow and is first charged to (+) by a primary charger 31 to which a high voltage is supplied from a high voltage power source 30. Next, in the exposure section 29, the original image is subjected to slit exposure, and at the same time, it is subjected to an AC static eliminating action by a static eliminator 32 to which AC high voltage is supplied from a power source 30, and then the surface of the exposure drum is exposed by a process of full-surface exposure using a lamp 33. forming an electrostatic latent image thereon. After being developed and imaged using a developer 35 in a developing device 34, the image is corona charged by a (-) high voltage applied to a post-charger 36, and excess developer is squeezed out without disturbing the image. . The transfer paper P fed from the paper feed section by a roller 37 or the like is separated by a separation belt 39 and guided to a drying/fixing section 40 . The transfer paper P is heat-fixed in the fixing section 40, and after the charge remaining on the surface is removed by the static eliminator 47, it is sent out from the ejection port onto the tray 49 by the ejection roller 48. The ejected transfer paper P is stacked with the copy side facing up and the last page number of the document facing down. When all the stacked originals have been copied in this way, both the sheet originals and the transfer paper are stored in the page order of the originals stacked on the first stacking table 23, thereby eliminating the loss of time for replacing the page order.

In the above copying machine, roller 1 at the end of the exposure section
If a jam occurs near 0 and near the rollers 11 and 12 of the guide plate 14 that reverses the sheet, and the sheet discharge to the tray 92 is delayed, the jam will be enlarged by subsequent sheets and the important document will be damaged.

In this example, the light source 21 and the light receiving element 22, which normally detect the leading edge of the sheet and temporarily stop it, are used as the first detection means for detecting the jam, so that the jam does not expand.
This detects the trailing edge of the sheet that has started to be conveyed again, and activates the first timer in FIG. Then, it is determined whether or not the sheet is delayed by a second detection means including a light source 120 and a light receiving element 121 provided near the discharge port. Further, the second detecting means detects the leading edge of the sheet, cancels the first timer, and at the same time activates the second timer.
Detect the upper stuck jam.

Further, sheet originals may have holes for files or portions with greatly different light transmittances. For example, when a sheet with holes for files is fed from the hole row side, the detection signal when moving from the sheet section to the hole is received as the sheet trailing edge signal, and the detection signal when moving from the hole to the sheet section is received as the sheet leading edge signal. Element 22
outputs. The timer is activated by this erroneous signal, causing a malfunction in jam detection.

In this example, this erroneous signal is removed by an integrating circuit, and the signal of only the actual leading edge or trailing edge of the sheet is used as the input signal.

An example of the jam detection circuit for the above will be described in detail with reference to FIG. 3. In the connection relationship, the DC power supply for this circuit is obtained from the power supply inside the copying machine via connectors J2-10 and J2-1. +24V, ground 0V is connected to B. The sheet detection signal C from the light source 21 and the light receiving element 22 shown in FIG. 2 is set to +24V from another circuit (not shown) and is inputted to this circuit via the connector J1-2. The input connector J1-2 is connected to the emitter of the transistor _Q1 , the resistors _R2 and _R3 , and the cathode of the diode _D1 .
The base of Q ₁ is connected to the collector of transistor Q ₂ through a resistor R ₄ , and the base of transistor Q ₂ is connected to a capacitor C ₃ through a Zener diode ZD ₁ to form an integrator circuit for the input signal C. .
The collector of the transistor Q ₁ is connected to the resistor R ₅ and the cathode of the diode D ₃ via the capacitor C ₄ to form a differentiating circuit, and the anode of the diode D ₃ is connected to the transistor that forms the monostable multivibrator for the first timer. Connected to the collector of Q ₃ and to the base of transistor Q ₄ via capacitor C ₇ . The base of transistor Q ₃ is reverse biased by resistor R ₆ so that normally transistor Q ₃ is off and thus transistor Q ₄ is on. The timer period is set by resistor _R5 and capacitor _C7 . Diode _D4 is for protection of transistor _Q4 . The collector of the transistor Q ₄ is connected to the base of the transistor Q ₅ of the inverter through the resistor R ₁₇ , and the collector of the transistor Q ₅ is connected to the base of the transistor Q 5 of the inverter through the capacitor C ₆ of the differentiating circuit to the resistors R ₁₆ , R ₁₇ , the diode D ₆ , the transistor Connected to _Q7 collector. Resistor R ₂₇ connects to the thyristor through diode D ₇
The anode of thyristor Q ₆ is connected to the jam detection light emitting _diode D ₁₀ .

To explain the operation, when the sheet is inserted now, the capacitor C ₃ is charged via the resistor R ₃ by the detection signal, and when the Zener diode ZD ₁ reaches the break voltage due to the charging potential, the transistor Q ₂ becomes conductive.
Then transistor Q ₁ conducts and capacitor C ₄
It produces an output of 24V. However, the 24V rising signal corresponding to the tip of the sheet is blocked by diode _D3 , so the monostable multi is not activated. Therefore, while the sheet is temporarily stopped and the light receiving element 22 is detecting the sheet, the first timer does not start operating.
The drum 24 of the copying machine rotates to a predetermined position and the sheet starts to be conveyed again, and the rear end of the sheet reaches the light receiving element 2.
2, the input signal changes to 0. A negative trigger pulse is therefore generated by the instantaneous capacitor C ₄ and diode D ₃ . The monostable multi is activated by this pulse. That is transistor Q ₃
The collector potential of and the base potential of transistor _Q4 decrease, turning off transistor _Q4 . As a result, the collector potential rises, turning on transistors _Q3 and _Q5 . This on state continues until capacitor _C7 is charged and transistor _Q4 is turned on. Then, when transistor Q ₄ turns on, transistor Q ₅ changes from on to off,
Capacitor C ₃ will then generate a positive trigger pulse that activates thyristor Q ₆ .
That is, after the time required for the leading edge to reach the second light receiving element 121 after the light receiving element 22 detects the trailing edge of the sheet, the position detection signal is output.

Here, if the sheet has a hole for a file, the hole causes the light receiving element 22 to generate a pulse similar to that when the trailing edge of the sheet is detected. However, due to the file hole near the tip of the sheet, the sheet detection signal does not have enough width to charge the capacitor _C3 to the break potential of the Zener diode _ZD1 , so the transistors _Q2 and _Q1 cannot be activated.
Therefore, the monostable multi is not driven by an erroneous signal caused by the hole.

Next, to explain the part for determining whether or not a delay jam has occurred, in the configuration, the light receiving element 121 is connected to +24V via a resistor R ₂₉ and an adjustment resistor VR ₁ .
R ₂₇ to operational amplifier Q ₁₁ input terminal 3, resistor
Connected to earth via R ₃₁ . Arithmetic amplifier
_Q11 outputs a low level (approximately +2V) output to terminal 6 when the light receiving element 121 receives light from the light source 120.
output, and when the light is blocked, a high level (+
24V). Output terminal 6 is connected to the base of transistor Q ₇ via resistor R ₂₅ and to the base of transistor Q ₁₉ via resistor R ₅₃ . The collector of transistor _Q7 is connected to the differential capacitor _C3 .

That is, when the sheet is detected by the light receiving element 121, a high level is output from the output terminal 6 of the operational amplifier _Q11 , so that the transistor _Q7 is turned on. Therefore, when the sheet is normally conveyed and reaches the light receiving element 121, the jam detection pulse from the monostable multi-layer is armed by the transistor _Q7 and does not operate the thyristor _Q5 , so that no jam is displayed. However, if there is a delay during sheet movement or a paper jam occurs, transistor Q ₇ remains off, so thyristor Q ₆ is activated by the pulse from the monostable multi, and light emitting diode D ₁₀ lights up to indicate a jam.

Next, I will explain the part of the safety circuit that operates together with this jam display.
The anode of D ₁₀ is a zener diode ZD ₃ and a resistor R ₂₀
connected to the base of transistor Q ₃ through
The collector of transistor Q ₃ is connected through a resistor R ₂₄ to the base of transistor Q ₉ . Furthermore, the collector of transistor _Q9 is connected to the emitter of transistor _Q10 . SL ₁ is a plunger for rotating rollers 6, 7, 8, and 9 in the sheet document feeding section, SL ₃ is a plunger for rotating rollers 9, 9' of the main body, and MS ₁
is a micro switch and connector J1-7 that is turned on when the sheet document feeder is attached to the document table 91.
is connected to a plunger (not shown) which stops the rollers 9, 9'.

That is, when thyristor Q ₆ is inactive, transistors Q ₈ and Q ₉ are activated, so plungers SL ₁ and SL ₃
can operate in response to a signal from the connector J1-3 synchronized with paper feeding from the copying machine main body, and automatically feeds stacked original sheets. But the thyristor
When Q ₆ is activated and produces a jam signal, transistors Q ₈ and Q ₉ are turned off and there is no signal to drive plungers SL ₁ and SL ₂ . transistor at the same time
Since _Q10 is turned on, the stop plunger operates to stop the timing rollers 6, 7, 8, and 9 and interrupt automatic paper feeding. Therefore, when a jam occurs, conveyance of subsequent sheets is stopped to prevent the jam from expanding.

Next, to explain the detection when a sheet jams on the light receiving element 121, due to the structure, the transistor
The collector of Q ₁₈ is connected to the anode of switch element Q ₁₇ via resistor R ₅₀ and diode D ₁₂ , and also to capacitor C ₁₃ . Switch element Q ₁₇
A programming voltage divided by resistors _R47 and _R48 is applied to the gate of the switch element Q17, and the cathode of the switch element _Q17 is connected to the gate of the thyristor _Q6 .

That is, when the leading edge of the sheet reaches the light receiving element 121, the output of the operational amplifier _Q11 turns on the transistor _Q19 and turns off the transistor _Q18 . The capacitor _C13 then starts charging at a predetermined time constant via the resistor _R49 . When the charging potential reaches the gate potential of switch element _Q17 , switch element _Q17 is turned on. Here, the adjustment resistor VR ₃ determines the charging time longer than the time required for the sheet to pass over the light-receiving element 121, and is variable depending on the length of the sheet, for example, depending on the button that displays the size of the sheet. be. Therefore, after the leading edge of the sheet is detected, the sheet passes normally through the light receiving element 121, and when the trailing edge of the sheet is detected, the output of the operational amplifier _Q11 decreases and the transistor _Q18 is turned on. Therefore, the electric field of capacitor C ₁₃ is discharged through diode D ₁₂ and thyristor Q ₆
Do not turn on switch element _Q17 such as turning on. In other words, no jam signal is generated. However, if the sheet stops there regardless of whether it reaches the light-receiving element 121, the switch element _Q17 is turned on, which triggers the thyristor _Q6 , displays a jam on the light-emitting diode _D10 , and stops driving the rollers in the same way as above. automatic paper feeding is interrupted.

Note that the resistor R ₁₅ and the capacitor C ₉ connected to the capacitor C ₈ via the diode D ₆ cause the capacitor C ₉ to absorb the transiently generated positive pulse since the transistor Q ₅ is off when the power supply of 24 V is turned on.
Therefore, thyristor _Q6 will not operate due to a malfunction when the power is turned on. Further, the counter CNT ₁ counts sheets, and erroneous counting is prevented by the above-mentioned integrating circuit. Capacitor C ₁ , C ₂ resistance R ₁ is
This is to further smooth the 24V power supply.

Another example of the present invention will be explained with reference to FIG. 4. Due to the structure, the transistor in the integrating circuit in FIG.
An inverter circuit consisting of a transistor _Q20 is connected to the collector of _Q1 , and when the input signal C is detected as a sheet, the potential is zero, and when it is not detected, the potential is +24V. With this configuration, the short width pulse input signal due to the hole in the sheet is absorbed by the capacitor _C3 , so it is not output from the transistor _Q1 ,
Therefore, regardless of the hole, the transistor _Q1 remains off while the sheet is present, so the collector potential of the transistor _Q20 remains at 24V. When the trailing edge of the sheet is detected, the collector potential of transistor Q ₂₀ drops from 24V to 0V, and diode D ₃ outputs a negative pulse to activate the monostable multi. At this time, the charging time of the capacitor _C3 should be equal to or less than the interval between sheets in continuous autofeed.

As described above, the present invention detects the rear end of the moving member,
Jam detection is performed by determining whether the movement of the moving member is completed within a predetermined time after detecting the trailing end, so the predetermined time setting can be shortened, and moreover, it is possible to continuously feed the moving member before it is discharged outside the moving path. It is possible to detect jams for each moving member in the auto feed.

[Brief explanation of the drawing]

Fig. 1 is an example of a block diagram of a jam detection device according to the invention, Fig. 2 is a sectional view of a copying machine with an auto feeder using the invention, Fig. 3 is an example of a jam detection circuit according to the invention, and Fig. 4 is a block diagram of a jam detection device according to the invention. This is another example of the jam detection circuit according to the present invention, and in FIG. 1, S ₁ : first detection means for detecting the trailing edge _of the sheet;
Timer means, D ₁ : First discrimination means.

Claims (1)

[Scope of utility model registration request] A first sheet detection means provided on the sheet movement path, a second sheet detection means provided downstream of the sheet conveyance with respect to the first detection means, and a second sheet detection means provided on the first sheet detection means after the sheet. a timer means for performing a time-limiting operation for the time required for the leading edge of the same sheet to reach the second sheet detecting means after the end of the sheet has completed passing; means for detecting and starting the timed operation of the timer means; and a jam upon completion of the timed operation of the timer means when the leading edge of the sheet does not reach the second detection means before the timed operation of the timer means is completed; A jam detection device comprising a jam warning means for outputting a signal, and a means for not starting the timed operation of the timer means for a predetermined time corresponding to the file hole after the first detection means has performed the detection operation. .