JP2002211796A - Sheet jamming detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of surely detecting a jammed sheet and a sheet remaining in a feed due to jamming. SOLUTION: This sheet jamming detector comprises a detection means Sn installed at appropriate positions of the sheet feed route 10 and detecting the pass of a fed sheet Pn and a control means 20 judging the feeding conditions of the sheet Pn based on the results of detection by detection means Sn. Each detection means Sn comprises a count part Cn for counting the pass of the front end of the sheet and a count part Cn for counting the pass of the rear end of the sheet Pn. The control means 20 compares these count parts Cn to judge the feeding conditions of the sheet Pn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is configured to discharge a remaining sheet on a sheet conveying path after processing a sheet causing a jam while checking the conveyance of each sheet. The present invention relates to a jam detection device.

[0002]

2. Description of the Related Art Conventionally, as a jam detection device, a Japanese Utility Model No. 53
There is an apparatus described in US Pat. This jam detection device is provided with a plurality of detectors for detecting the passage of a sheet at an appropriate position on a path along which the sheet is conveyed, and the conveyance of the sheet from the detector to the next detector sequentially passes. Is measured by a timer, and if it does not pass within a predetermined time, it is determined that a jam has occurred.

[0003]

In a device such as a high-speed printer or a copying machine, a plurality of sheets exist on a sheet conveying path of the device when performing continuous printing (or copying). In this case, when a jam occurs, the above-described jam detection device stops the sheet on the sheet conveyance path, and cannot measure the passage of the sheet. At the time of the stop, the sheet detection starts. For this reason, it is difficult to accurately check the conveyance of the sheet after the sheet causing the jam (hereinafter, referred to as a “jam sheet”) is removed.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a jam detecting device capable of reliably detecting a jam sheet and a sheet remaining on a conveyance path due to the jam. I do.

[0005]

In order to solve the above-mentioned problems, first detecting means provided at an appropriate position in a sheet conveying path and detecting passage of a conveyed sheet, and a detection result of the detecting means, Control means for judging the sheet conveyance state, each detecting means includes a counting unit for counting that the leading end of the sheet has passed, and a counting unit for counting that the trailing end of the sheet has passed, The control means
It is characterized in that these count units are compared to determine the sheet conveyance state.

Further, each counting section includes a first counting section for counting that the leading end of the sheet has passed, a second counting section for counting that the trailing end of the sheet has passed, and a sheet A third counting unit that counts that the leading end of the sheet has passed when discharging, and a fourth counting unit that counts that the trailing end of the sheet has passed when discharging the sheet after processing the sheet jam. It is characterized by having.

When the sheet is normally conveyed, the control means detects the first count of the detection means, the first count of the next detection means, the second count of the detection means, and the next detection. The second counting unit of the means is compared with each other to determine the sheet conveyance state, the sheet is not conveyed, the sheet causing the sheet is processed, and the sheet remaining on the sheet conveyance path is discharged. In the case, the sum of the first counting unit of the detecting means and the third counting unit of the detecting means,
While comparing the sum of the first counting section of the next detecting means and the third counting section of the next detecting means, the sum of the second counting section of the detecting means and the fourth counting section of the detecting means, The conveyance state of the sheet is determined by comparing the sum of the second counting unit of the detecting unit and the sum of the fourth counting unit of the next detecting unit.

On the sheet conveying path, there is provided one or more cover members disposed between one of the detection means or each of the detection means, and the cover member is connected to the control means to detect opening of the cover member. It is characterized by comprising detecting means.
Specifically, the sheet conveyance path has a sheet supply unit to a sheet discharge unit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a sheet jam detection device applied to the present invention. The sheet jam detecting device is provided with a sheet conveying path 10 for conveying a sheet to a predetermined place.
And one or more provided at appropriate places in the sheet transport path 10,
Detecting means Sn for detecting passage of conveyed sheet Pn
(Where N ≧ 1), a detection unit Dn, one or more cover members An disposed between the detection units Sn or between the detection units Sn, and detection results of the detection unit Sn and the detection unit Dn. Control means 20 for checking the conveyance of the sheet Pn based on the

[0010] The detecting means Sn includes a counting section Cn.
A micro switch, a photo interrupter, a reflection type sensor, or the like is connected to the control unit 20. Further, the counting section Cn includes a first counting section Cn1 for counting that the leading end of the sheet Pn has passed, and a sheet Pn.
Counting section C that counts that the rear end of
n2, a third counting unit Cn3 that counts that the leading end of the sheet Pn has passed when the sheet Pn is discharged after the sheet P is jammed, and a sheet when the sheet Pn is discharged after the sheet Pn is jammed. A fourth counting section Cn4 for counting that the rear end of Pn has passed.

The cover member An is arranged on one of the detecting means or between the detecting means on the sheet conveying path. The detecting means Dn is provided on each of the cover members An. Each detecting means Dn is provided when the sheet is not conveyed at a predetermined timing, for example, when a jam occurs,
When the cover member An located on the sheet causing the opening is opened, the operation is detected. In this embodiment, the detecting means Dn is a micro switch, a photo interrupter, a reflection sensor, or the like, like the detecting means Sn. The detecting means Dn includes:
It is connected to the control means 20 like the detection means Sn.

FIG. 2 shows an outline of the control means 20. The control means 20 checks the conveyance of the sheet Pn.
A ROM 22 in which a program for checking the conveyance of the sheet Pn is written, a RAM 23 for temporarily storing detection results of the detection unit Sn and the detection unit Dn,
Timer 24 that measures the operation time of the sheet jam detector
Is provided. The detecting means Sn and the detecting means Dn are connected via an interface 25.

FIG. 3 shows a sheet conveying path 1 according to the present invention.
9 shows a flowchart for performing a transport check of 0. When printing is started, as shown in FIG.
On P.0, the sheet Pn is continuously conveyed. Detecting means S
n detects the passed sheet Pn and sends the detection result to the control means 20. At this time, the first counting section Cn1 counts one when the leading edge of the sheet Pn passes, and the second counting section Cn2 counts one when the trailing edge of the sheet Pn passes (step 1).

Next, it is determined whether a jam has occurred (step 2). In this step, the jam is determined based on whether or not the count number of the first count unit Cn1 and the count number of the second count unit Cn2 are the same. If these count numbers are the same, control means 2
If 0 is determined, there is no jam, and the detection of the jam ends. Conversely, if the counts are different, it is determined that a jam has occurred, and the process proceeds to the stop processing of the sheet conveying path 10 for the jam (step 3).

In the stop processing of the sheet conveying path 10, when the jam is determined in step 2, the control means 20
The conveyance of the sheet Pn is stopped, and the determined location of the occurrence of the jam is output to display means (not shown) to notify the user. For example, FIG. 4 shows a count state of each detection means Sn in FIG. Note that, in FIG. 1, the direction of the arrow is the conveying direction of the sheet Pn. When a certain sheet P1 (here, the top) causes a jam, the difference between the counts that have passed the leading end of the sheet Pn is two between C11 and C21, and three between C21 and C31. P
The difference between the counts that have passed through the rear end of the sheet Pn that has not been detected between the detection units (S11 to S13) is two, for example, between C12 and C22, and two between C22 and C32. You can know. The counted number is used at the time of a conveyance check of the sheet conveyance path 10 described later. When the user removes the jam sheet P1, the detecting means Dn provided in the removed area
(Here, the third detection means S3) detects this, and sends the detection result to the control means 20. At this time, the third counting section Cn3 and the fourth counting section Cn4 provided in each detecting means Sn are set so that the leading and trailing ends of the sheet Pn can be counted. Third counting section C at this time
The count numbers of n3 and the fourth count unit Cn4 are zero.

When the detecting means D3 detects this, that is, when the processing of the jammed sheet P1 is completed, the control means 20 checks the conveyance of the sheet conveying path (step 6). This step is performed by each of the counting units C described above.
In addition to n1 and Cn2, the counting is performed by the corresponding third and fourth counting units Cn3 and Cn4. The third counting unit Cn3 and the fourth counting unit Cn4 are counted at intervals of one from the time when the sheet Pn stops.
For example, after performing the jam processing in FIG. 4, the sheet Pn is transported again. In this state, the last part of the sheet P7 is the end of the conveyance.

In this state, first, the detecting means S1 and the second detecting means S2 are compared. More specifically, the sum of the number of counts passed by the leading end of the sheet Pn, that is, C11
And the sum of C13 and C21 and C23. Further, the sum of the number of counts passed by the rear end of the sheet Pn, that is, the sum of C12 and C14, and the sum of C22 and C24 are compared. At this time, if the respective sums are different, it is determined that a jam has occurred in the detecting means S1n,
Return to step 4. Also, if their sums are equal,
It is determined that the conveyance of the sheet Pn (discharge of the sheet Pn) is normally performed, and the sum of CN21 and CN23 and C
Comparison of the sum of N31 and CN33, and furthermore, CN22 and C33
The sum of N24 and the sum of CN32 and CN34 are compared (comparing the second detection means S2 and the third detection means S3). If the sums are different, the process returns to step 4 (step 7).

When the user removes the jam sheet P1 and the other sheets Pn, for example, in FIG. 1, the detecting means Dn provided in another area (here,
A case will be described in which the sheet in the second detection means S2) is removed, and the detection means D2 detects that the sheet has been jammed. In this state, when step 4 is executed, the second detecting means S2 and the third detecting means S3
In this case, the count numbers of the respective count units Cn do not match. For this reason, the control unit 20 determines that the detection result of the detection unit Dn is
When it is estimated that the sheet Pn other than the jammed sheet has been removed, the sheet Pn is detected between the detection means Sn (here, between S2 and S3).
Step 6 is performed, ignoring the detection result of.

As described above, when a jam occurs by counting the leading and trailing edges of the passed sheet, the jam is processed, and the sheet is detected from the time when the sheet is stopped. (P1, P2, P3, P4, and P6) that have not been detected by the detecting means Sn + 1 can be reliably transported.

[0020]

As described above, regardless of the printing capacity, the length of the sheet conveyance path, and the size of the sheet, the jam on the sheet conveyance path can be reliably detected and the sheet remaining on the sheet conveyance path can be detected. Can be processed.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a sheet jam detection device applied to the present invention.

FIG. 2 is a diagram showing an outline of control means.

FIG. 3 is a diagram illustrating a flowchart for performing a transport check.

FIG. 4 is a diagram illustrating a conveyance check state of each detection unit.

[Explanation of symbols]

 Reference Signs List 10 sheet transport path 20 control means Pn sheet Sn detection means Dn detection means Cn counting section An cover member

Claims (6)

[Claims] A first detecting unit provided at an appropriate position in a sheet conveying path to detect passage of a conveyed sheet; and a control unit configured to determine a sheet conveying state based on a detection result of the detecting unit. Wherein each of the detection means includes a counting section that counts that the leading end of the sheet has passed, and a counting section that counts that the trailing end of the sheet has passed, and the control means A sheet clogging detecting device for comparing the parts and determining a conveyance state of the sheet. 2. Each of the counting units includes a first counting unit that counts that the leading edge of the sheet has passed, a second counting unit that counts that the trailing edge of the sheet has passed, and a sheet that has been processed for sheet jamming. A third counting unit that counts that the leading end of the sheet has passed when discharging, and a fourth counting unit that counts that the trailing end of the sheet has passed when discharging the sheet after processing the sheet jam. The sheet jam detection device according to claim 1, further comprising: 3. The control device according to claim 1, wherein when the sheet is normally conveyed, the control unit includes a first count unit of the detection unit, a first count unit of the next detection unit, and a second count unit of the detection unit. And the following second counting unit of the detection means,
When the sheet is not conveyed, the sheet is not conveyed, the sheet causing the sheet is processed, and the sheet remaining on the sheet conveying path is discharged. The sum of the first counting unit and the third counting unit of the detecting means, and comparing the sum of the first counting unit of the next detecting means and the third counting unit of the next detecting means, The sum of a second counting section of the detecting means and a fourth counting section of the detecting means,
3. The sheet conveyance state according to claim 1, wherein a state of the sheet is determined by comparing a sum of a second count unit of the next detection unit and a fourth count unit of the next detection unit. Sheet jam detector. 4. The apparatus according to claim 1, further comprising: one or more cover members disposed on the sheet conveying path, the cover member being disposed between one of the detection means or each of the detection means, the cover member being connected to the control means, 4. The sheet jam detecting device according to claim 1, further comprising a detecting unit configured to detect opening of the cover member. 5. The control device according to claim 1, wherein when the control unit detects that any of the cover members has been opened, the control unit determines a sheet conveyance state based on a detection result other than the detection unit in the open area. Claim 1, 2, 3 or 4
A sheet jam detection device according to the above. 6. The sheet jam detection device according to claim 1, wherein the conveyance path has a sheet supply unit to a sheet discharge unit.