JP2005195808A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of preventing the lowering of productivity, by preventing the rear-end collision of succeeding paper against preceding paper and minimizing waiting for a paper interval, by storing information on the preceding paper started from a resist, until the succeeding paper starts from the resist. <P>SOLUTION: When the preceding paper reaches a resist start point 8 (S201), whether it is paper to be reversed and ejected is checked (S202). If it is to be reversed and ejected, a reversal timer, according to the length of the paper itself äto calculate by an expression (1): [route of reversed ejected paper] + [length of paper]} and a maximum size timer äto set the length of the preceding paper obtained by an expression (2): [length of preceding paper] + [length of succeeding paper] as the maximum length} are set (S203). Furthermore, information on the preceding paper (for example, paper size, length, reversed ejected paper or straight ejected paper or the like) is set (S204), and the paper starts from the resist (S205). When determining in step S202 that it is not the paper to be reversed and ejected, the timer is reset so that paper before the preceding paper does not exert influence (S206) and the operation advances to the step S204. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to a technology for preventing a rear-end paper and a rear-end paper from colliding in an interleaf mode.

The interleaf mode is a mode in which a plurality of transfer sheets coexist in the conveyance path simultaneously during continuous image forming operations. In order to explain the prevention of the collision between the preceding sheet and the succeeding sheet in this mode, The movement of the transfer sheet of the image forming apparatus will be described. FIG. 3 is a layout diagram of a transfer paper conveyance system of a general image forming apparatus. The transfer paper fed from each paper feed stage (the first paper feed 1 to the fourth paper feed 4, the manual paper feed 5, the LCT 6) sends a write request at the write request point 7 and then to the registration start point 8 Then, the timing between the latent image written on the photosensitive drum from the LD and the transfer position is adjusted (stopped and started), and the process proceeds to the transfer position 9, the fixing 14, and the paper discharge port 13. Here, in this layout example, a straight discharge route 15 (face-up discharge) indicated by a one-dot broken line and a reverse discharge route 16 (face-down discharge: face-down discharge: switching point 17 indicated by a one-dot broken line are arranged downstream of fixing. There are two types of transport paths, such as “backing”, and an output form that meets the user's request can be selected. When straight paper discharge continues, the transfer paper can be continuously conveyed while maintaining the minimum paper space (necessary for sensor ON / OFF recognition). However, there is a transfer paper (referred to as preceding paper) that performs reverse paper discharge. If it is in between, further paper space is required between the transfer paper (hereinafter referred to as trailing paper) to be conveyed next.
More specifically, if the preceding paper is reverse paper discharge and the subsequent paper is straight paper discharge, the subsequent paper catches up at the paper discharge port 13 if the subsequent paper is passed without waiting. Paper route 16 (reversing entrance 11 to switching point 17 to reversing exit 12) + paper length (1) A space between “reversing timer” is required.
When the preceding paper is reverse paper discharge and the following paper is reverse paper discharge, if the trailing paper is shorter than the preceding paper, the succeeding paper catches up at the switching point 17, so the preceding paper length− Follow-up sheet length (2) A sheet gap of “size difference timer” is required.
In order to prevent this "follow-up paper catch-up", the conventional method is as shown in the flowchart of FIG. In order to simplify the description, the distance between the reversal entrance to (straight) to the reversal exit is 0, the distance between the write request point to the resist start point is 0, and from the transfer position to the resist start point and the LD irradiation point. It is assumed that the distance is the same, the minimum required paper interval is 0, and LD writing starts immediately by sending a write request.
4A shows the control flow for the preceding paper, FIG. 4B shows the control flow for the cycle timer, and FIG. 4C shows the control flow for the following paper. In the conventional example, the transfer paper cannot be stopped after the resist, and mediation is performed with the resist in order to open a gap between the papers.
The preceding sheet control flow in FIG. 4A will be described. First, if the preceding paper is sent at the timing (S101) at which a write request is sent and it is to perform reverse paper discharge (S102), the "reverse timer" (according to the above equation (1)) according to the length of the paper of its own. (Calculation) is set (S103), and the process ends. If the paper is not reversed in step S102, the timer is reset (S104) and the process ends.
Next, the periodic timer control flow in FIG. 4B will be described. When the periodic timer reaches a certain time, each timer (timer value) is decremented (S110), and when the time is up (timer value = 0) (S111), the wait flag corresponding to the timer is released (S113).
Next, the following sheet control flow in FIG. When the succeeding paper reaches the write request point 7 (S121), if the succeeding paper itself is reversed paper discharge, the preceding paper is searched (S123). S124) When the length of the succeeding paper is shorter than the length of the preceding paper (S125), the “size difference timer” (calculated by the above equation (2)) is set, and the wait flag is set (S126). Wait at registration start point 8. When the wait flag is released by the cycle timer (S127), a write request is sent (S131). In step S122, if the succeeding sheet itself is a straight sheet discharge, it is determined whether the “reverse timer” is set (S128). If it is set, a wait flag is set (S129), and the registration start point 8 is set. Wait at. When the wait flag is canceled by the cycle timer (S130), a write request is sent (S131). In order to prevent a collision at the paper discharge port 13 or the switching point 17 in such a flow, a paper gap is provided with a resist.

However, if the preceding paper is reversed paper discharge and the succeeding paper is reverse paper discharge in FIG. 4, the preceding paper is searched in FIG. 4C (S123). There was no information left, and it was not possible to wait for the paper interval that was originally necessary, and the following paper could catch up. Even when a preceding sheet is found, the position of the preceding sheet at that time is not taken into consideration, and there is a possibility that productivity may be reduced unnecessarily by waiting for an unnecessary interval between sheets.
In view of such a problem, the present invention stores information on the preceding paper that has started registration until the succeeding paper further starts registration, prevents the trailing paper from colliding with the preceding paper, and waits between papers. An object of the present invention is to provide an image forming apparatus which is minimized and prevents a decrease in productivity.

In order to solve such a problem, the present invention provides an image forming apparatus that operates in an interleaf mode in which a plurality of transfer sheets exist in a conveyance path during a continuous image forming operation. A reversing timer that counts the time required for the paper to be reversed and discharged; a size difference timer that counts a time difference between the preceding transfer sheet and the succeeding transfer sheet; and a preceding sheet information storage unit that stores necessary information about the preceding transfer sheet. , Provided.
Conventional image forming devices that operate in the interleaf mode do not store various types of information on the preceding paper, so there is a risk that it will collide with the following paper, and the waiting time between papers will be unnecessarily large, resulting in higher productivity. Had fallen. Therefore, in the present invention, various types of information on the preceding paper are stored, and the succeeding paper determines the optimum sheet interval from the information and determines the registration start timing. Here, when a plurality of transfer sheets are simultaneously on the conveyance path, for example, when attention is paid to two transfer sheets, the transfer sheet that is discharged first is referred to as a preceding transfer sheet, and is next to the preceding transfer sheet. For convenience, the transfer paper discharged to the rear is called a subsequent transfer paper.
According to this invention, the reversing timer for counting the time required for the reversing and discharging of the transfer paper, the size difference timer for counting the passing time difference between the preceding transfer paper and the succeeding transfer paper, and necessary information on the preceding transfer paper are stored. Leading paper information storage means, so even if the preceding paper is completely discharged out of the machine and disappears, the resist waits for the time required to prevent the trailing paper from colliding or waits unnecessary Therefore, it is possible to perform a transport operation that is stable and does not reduce productivity.
According to a second aspect of the present invention, when the preceding transfer sheet reaches the registration start point and the preceding transfer sheet is set to perform the reverse discharge, a predetermined time is set in the reverse timer and the size difference timer. In addition, after the predetermined information is stored in the preceding sheet information storage means, the preceding transfer sheet is conveyed from the registration start point.
A reversing timer that counts the time required for reversing in order to prevent the trailing paper from catching up and colliding when the preceding transfer paper has reached the registration start point and is set to perform reversal paper discharge; A size difference timer that counts the difference in passage time between the preceding paper and the following paper is set to a predetermined value. Further, for example, the paper size, the paper length, information on whether the paper is reversed or straight is stored in the preceding paper information storage means. Thereafter, the preceding paper is conveyed from the registration start point.
According to this invention, when the preceding transfer paper reaches the registration start point and the preceding paper is set to perform reverse paper discharge, a predetermined time is set in the reverse timer and the size difference timer, After the predetermined information is stored in the preceding sheet information storage means, the preceding sheet is conveyed from the registration start point, so that the succeeding sheet can recognize all the information on the preceding transfer sheet, and the succeeding sheet has the optimum timing. You can start registration points.
According to a third aspect of the present invention, when the preceding transfer sheet reaches the registration start point, the reversing timer and the size difference timer are reset when the preceding transfer sheet is set not to perform the reversal discharge. Features.
When straight discharge is performed when the preceding transfer sheet reaches the registration start point, it is not necessary to set a time for each timer. The reason is that when the preceding paper is straight paper discharge, the preceding paper is always discharged in time, so there is no need to set an unnecessary time. Therefore, in that case, the timer is reset.
According to this invention, when the preceding transfer sheet reaches the registration start point, if the preceding transfer sheet is set not to perform the reverse discharge, the reversing timer and the size difference timer are reset. Therefore, it is possible to prevent an erroneous influence on the determination of waiting for the succeeding sheet by setting the waiting information.

According to a fourth aspect of the present invention, when the succeeding transfer paper reaches a point where data writing is requested, the succeeding transfer paper is set to perform the reverse discharge, and the preceding transfer paper is also the reverse discharge. If it is determined that the succeeding transfer sheet is shorter than the preceding transfer sheet, the data write request is stopped until the time of the size difference between the two transfer sheets elapses. And
When the succeeding paper reaches the point where data writing is requested, if the preceding paper and the succeeding paper are both set to perform reverse paper discharge, the paper length of the following paper is shorter. If the timing of writing as a star is too fast, there is a risk of a rear-end collision. Therefore, in the present invention, the writing is started after waiting for a difference time from the preceding paper, and the timing is delayed.
According to this invention, when the succeeding sheet reaches the point where data writing is requested, the succeeding sheet is set to perform reverse discharge, and the preceding sheet is also set to perform reverse discharge. In this case, if it is determined that the succeeding sheet is shorter than the preceding sheet, the data write request is stopped until the time of the size difference between the two transfer sheets elapses. A rear-end collision can be prevented.
According to a fifth aspect of the present invention, when the transfer paper does not go directly to the paper discharge outlet but goes to the duplex unit, necessary information on the preceding transfer paper, the reverse timer and size difference timer, and waiting processing as the succeeding transfer paper are performed. It is characterized by not.
When the double-sided conveyance mechanism is provided downstream from the reversing unit, the paper does not go directly to the paper discharge port, but goes to the write request point and the registration start point to transfer the back image again. That is, in this case, the influence at the paper discharge port is eliminated. Accordingly, if the control flow for the preceding paper and the succeeding paper is entered here, incorrect information is set, and the control for the succeeding paper that is next directed to the paper discharge port is adversely affected.
According to this invention, when the transfer paper is not directly directed to the paper discharge outlet but to the duplex unit, the necessary information of the preceding paper, the reversing timer and the size difference timer, and the waiting process as the succeeding paper are not performed. It is possible to prevent the adverse effect on the control of the succeeding paper toward the paper discharge port.

As described above, according to the first aspect of the present invention, the reversing timer for counting the time required for the reversal discharge of the transfer paper, the size difference timer for counting the passage time difference between the preceding transfer paper and the succeeding transfer paper, and the preceding transfer Since the preceding paper information storage means for storing the required information of the paper is provided, even when the preceding paper is completely discharged out of the machine, the resist waits for the time required to prevent the trailing paper from colliding, Alternatively, it is possible to perform a transport operation that is stable without unnecessary waiting and that does not reduce productivity.
Further, in the second aspect, when the preceding transfer paper reaches the registration start point and the preceding paper is set to perform reverse paper discharge, a predetermined time is set in the reverse timer and the size difference timer, After the predetermined information is stored in the preceding sheet information storage means, the preceding sheet is conveyed from the registration start point, so that the succeeding sheet can recognize all the information on the preceding transfer sheet, and the succeeding sheet has the optimum timing. You can start a registration point.
According to the third aspect of the present invention, when the preceding transfer sheet reaches the registration start point, if the preceding transfer sheet is set not to perform the reverse discharge, the reversing timer and the size difference timer are reset. Therefore, it is possible to prevent an erroneous influence on the determination of waiting for the succeeding sheet by setting the waiting information.
According to a fourth aspect of the present invention, when the succeeding paper reaches a point where data writing is requested, the succeeding paper is set to perform reverse paper discharge, and the preceding paper is also set to perform reverse paper discharge. In this case, if it is determined that the succeeding sheet is shorter than the preceding sheet, the data write request is stopped until the time of the size difference between the two transfer sheets elapses. A rear-end collision can be prevented.
According to the fifth aspect of the present invention, when the transfer paper does not go directly to the paper discharge outlet but goes to the duplex unit, the necessary information of the preceding paper, the reversing timer and the size difference timer, and the waiting processing as the succeeding paper are not performed. It is possible to prevent the adverse effect on the control of the succeeding paper toward the paper discharge port.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a schematic configuration diagram of a digital copying machine according to an embodiment of the present invention. This configuration is a copying machine 100 as an image processing apparatus, and a contact glass 206 is provided on the upper surface of the copying machine 100. In addition, an automatic document feeder (hereinafter simply referred to as ADF) 201 is provided on the upper side of the copying machine 100, and this ADF 1 is connected to the copying machine 100 via a hinge or the like (not shown) so as to open and close the contact glass 206. Has been. The ADF 201 separates documents one by one from a document tray 202 as a document placing table on which a document bundle composed of a plurality of documents can be placed, and faces the contact glass 206 from the document bundle placed on the document tray 202. The separation / conveying means that conveys the original and the document conveyed toward the contact glass 206 by the separation / conveying means are conveyed / stopped to a reading position on the contact glass 206, and the copy disposed below the contact glass 206 The document that has been read by the reading means (a known exposure lamp 251, mirrors 252, 255, 256, lens 253, CCD 254, etc.) 250 of the machine 100 is unloaded from the contact glass 206. The paper feed motor is driven by an output signal from the controller, and when the paper feed start signal is input from the copying machine 100, the controller drives the paper feed motor forward / reversely. When the paper feed motor is driven in the forward direction, the feed roller 203 rotates in the clockwise direction so that the uppermost original is fed from the original bundle and conveyed toward the contact glass 206. When the leading edge of the document is detected by the document set detection sensor 207, the controller rotates the paper feed motor in reverse based on the output signal from the document set detection sensor 207. This prevents subsequent documents from entering and prevents separation.

Further, when the document set detection sensor 207 detects the trailing edge of the document, the controller counts the rotation pulse of the conveyor belt motor from this detection point, and when the rotation pulse reaches a predetermined value, the controller By stopping the driving and stopping the feeding belt 204, the document is stopped at the reading position of the contact glass 206. Also, when the trailing edge of the document is detected by the document set detection sensor 7, the controller drives the paper feed motor again, separates the subsequent document as described above, and conveys the document toward the contact glass 206. When the pulse of the paper feed motor from the time when the original is detected by the original set detection sensor 207 reaches a predetermined pulse, the paper feed motor is stopped and the next original is put on standby. When the original stops at the reading position of the contact glass 206, the original is read and exposed by the copying machine 100. When this reading and exposure are completed, a signal is input from the copier 100 to the controller. When this signal is input, the controller drives the conveyor belt motor to rotate forward, and the document is transferred from the contact glass 206 by the conveyor belt 216. It is carried out to the discharge roller 205.
As described above, a document bundle placed on the document tray 202 in the ADF 201 with the image surface of the document facing up is pressed from the top document to the contact glass 206 when the print key on the operation unit is pressed. It is fed to a predetermined position. The fed original is read by the reading unit 250 after the image data of the original on the contact glass 206 is discharged to the discharge port A (discharge port at the time of reverse document discharge) by the feeding belt 204 and the reverse driving roller. Further, when it is detected that there is a next document on the document tray 202, it is fed onto the contact glass 206 in the same manner as the previous document.
The transfer sheets stacked on the first tray 208, the second tray 209, and the third tray 210 are fed by the first sheet feeding unit 211, the second sheet feeding unit 212, and the third sheet feeding unit 213, respectively, and are conveyed vertically. The unit 214 is transported to a position where it abuts on the photoreceptor 215. The image data read by the reading unit 250 is written on the photoconductor 215 by a laser from the writing unit 257, and a toner image is formed by passing through the developing unit 227. Then, the toner image on the photosensitive member 215 is transferred while the transfer paper is conveyed by the conveying belt 216 at the same speed as the rotation of the photosensitive member 215. Thereafter, the image is fixed by the fixing unit 217 and conveyed to the paper discharge unit 218. The transfer paper conveyed to the paper discharge unit 218 is discharged to the paper discharge tray 219 when the staple mode is not performed.

FIG. 2 is an operation flowchart of the image forming apparatus of the present invention. 2A is a control flow for the preceding paper, FIG. 2B is a control flow for the cycle timer, and FIG. 2C is a control flow for the following paper. A feature of the present invention is that information on the preceding sheet whose registration has been started is stored until the subsequent sheet is further registered. This will be described with reference to FIG. First, the preceding sheet control flow will be described with reference to FIG. First, when the preceding paper reaches the registration start point 8 (S201), it is checked whether or not it is reverse paper discharge (S202). If it is reverse paper discharge (YES route in S202), A reversing timer according to the length (calculated by the preceding formula (1)) and a maximum size timer (the preceding paper length of the preceding formula (2) is set to the maximum length (for example, double letter length, following paper length) (S203) is set (S203), and preceding paper information (for example, paper size, length, reverse discharge or straight discharge, etc.) is set (S204). Registration is started (S205) If the reverse paper discharge is not performed in step S202, the timer is reset so that the influence of the previous paper does not remain (S206), and the process proceeds to step S204.
Conventional image forming devices that operate in the interleaf mode do not store various types of information on the preceding paper, so there is a risk that it will collide with the succeeding paper, and the waiting time between papers will be unnecessarily large, resulting in higher productivity. Had fallen. Therefore, in this embodiment, when the preceding transfer sheet reaches the registration start point 8, the time required for reversing is set in order to prevent the trailing sheet from catching up and colliding when the sheet is set to perform reversal discharge. And a size difference timer for counting the difference in passage time between the preceding paper and the following paper are set to predetermined values. Further, for example, the paper size, the paper length, information on whether the paper is reversed or straight, etc. are stored in the preceding paper information storage means. Thereafter, the preceding paper is conveyed from the registration start point. As a result, even if the preceding paper is completely discharged out of the machine and disappears, the resist does not wait for the time required to prevent the trailing paper from colliding with it, or it is stable without unnecessary waiting, and productivity is improved. A transport operation that does not drop can be performed.
When straight paper is discharged when the preceding paper reaches the registration start point 8, there is no need to set a time for each timer. The reason is that when the preceding paper is straight paper discharge, the preceding paper is always discharged in time, so there is no need to set an unnecessary time. Therefore, in that case, the timer is reset, so that it is possible to prevent the wait determination of the succeeding paper from being erroneously set by setting wait information that is originally unnecessary.

Next, the periodic timer control flow in FIG. 2B will be described. When the period timer reaches a certain time, each timer (timer value) is decremented (S210), and when the time is up (timer value = 0) (S211), the wait flag corresponding to the timer is released (S213).
Next, the following sheet control flow in FIG. When the succeeding paper reaches the write request point 8 (S221), it is checked whether or not the succeeding paper itself is reversely discharged (S222). If it is reversely discharged (YES route in S222), Next, it is checked whether or not the preceding sheet is reversely discharged (S223). If the preceding sheet is also reversely discharged (YES in S223), it is determined whether or not the succeeding sheet is shorter than the preceding sheet. (S224) Based on the size difference timer set by the preceding paper, the preceding paper registration elapsed time (maximum size timer initial value−size timer value at that time) is calculated (S225), and this time is required due to the size difference. If the time has not elapsed (YES route in S225), a size difference timer (previously calculated from the above equation (2)-the above elapsed time), a wait flag is further set (S226), and a resist start point Wait. When the wait flag is canceled by the cycle timer (S227), a write request is sent (S231).
In step S222, if the succeeding sheet itself is a straight sheet discharge (NO route in S222), it is determined whether the reverse timer for the preceding sheet is set (S228), and if it is set (YES route in S228). ), A wait flag is set (S229), and the process waits at the registration start point 8. When the wait flag is canceled by the cycle timer (S230), a write request is sent (S231).
When the succeeding paper reaches the point 7 for requesting data writing, if both the preceding paper and the succeeding paper are set to perform reverse paper discharge, the paper length of the following paper is shorter. And if the timing of writing as a star is too fast, there is a risk of a rear-end collision. Therefore, in the present embodiment, the writing is started after waiting for the time difference from the preceding sheet, and the timing is delayed. As a result, rear-end collision can be prevented even when both transfer sheets are reversely discharged.
In order to prevent a collision at the paper discharge port 13 or the switching point 17 in such a flow, a paper gap is provided with a resist. In this embodiment, a double-sided transport mechanism is provided downstream from the reversing unit. In this case, there is no influence at the paper discharge port because it goes to the write request point 7 and the registration start point 8 to transfer the back image again without going directly to the paper discharge port. Therefore, if the control flow for the preceding sheet and the succeeding sheet is entered here, incorrect information is set, and the control of the succeeding sheet next to the paper discharge port is adversely affected. That is, in the case of going to both sides, the control flow of the preceding paper and the succeeding paper may be ignored at all.

1 is a schematic configuration diagram of a digital copying machine according to an embodiment of the present invention. 3 is an operation flowchart of the image forming apparatus of the present invention. FIG. 3 is a layout diagram of a transfer paper conveyance system of a general image forming apparatus. 10 is an operation flowchart of a conventional image forming apparatus.

Explanation of symbols

  1 First paper feed, 2nd paper feed, 3rd paper feed, 4th paper feed, 5 manual feed, 6 LC, 7 Write request point, 8 Registration start point, 9 Transfer position, 10 LD irradiation point , 11 Reverse entry, 12 Reverse exit, 13 Discharge outlet, 14 Fixing, 15 Straight discharge route, 16 Reverse discharge route, 17 Switching point

Claims (5)

An image forming apparatus that operates in an interleaf mode in which a plurality of transfer sheets exist in a conveyance path during a continuous image forming operation,
A reversing timer that counts the time required for the reversal discharge of the transfer paper, a size difference timer that counts a difference in passage time between the preceding transfer paper and the succeeding transfer paper, and a preceding paper information storage that stores necessary information of the preceding transfer paper And an image forming apparatus.   When the preceding transfer sheet reaches the registration start point and the preceding transfer sheet is set to perform the reverse discharge, a predetermined time is set in the reverse timer and the size difference timer, and the preceding transfer sheet is set. 2. The image forming apparatus according to claim 1, wherein after the predetermined information is stored in the paper information storage unit, the preceding transfer paper is conveyed from the registration start point.   The reversing timer and the size difference timer are reset when the preceding transfer sheet has been set so as not to perform the reverse discharge when the preceding transfer sheet reaches a registration start point. 2. The image forming apparatus according to 1.   When the succeeding transfer sheet reaches a point where data writing is requested, the succeeding transfer sheet is set to perform the reverse discharge, and the preceding transfer sheet is also set to perform the reverse discharge. 2. If it is determined that the succeeding transfer sheet is shorter than the preceding transfer sheet, the data write request is stopped until the time of the size difference between the two transfer sheets elapses. The image forming apparatus described in 1.   When the transfer sheet does not go directly to the paper discharge port but to the duplex unit, the necessary information of the preceding transfer sheet, the reversing timer and the size difference timer, and the waiting process as the succeeding transfer sheet are not performed. The image forming apparatus according to claim 1.

Images