JP2006091330A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of discharging sheets without generating another jam or without damaging them when abnormality such as the jam of the sheets occurs. <P>SOLUTION: A discharge control means for stopping the sheets staying inside an image forming apparatus main body and discharging the stopped sheets on the basis of prescribed priority when detecting occurrence of the jam performs control so as to preferentially discharge the sheet staying in a second sheet carrying route 502 to the merging part of first and second sheet carrying routes 502 and 503 between the sheets staying in the first sheet carrying route 503 where the sheet that has passed through at least a first fixing part 12 passes through and the second sheet carrying route 502 branched from the first sheet carrying route 503, where a second fixing part 15 is arranged and the sheet that has passed through the first fixing part 12 selectively passes through. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an apparatus that automatically discharges a sheet staying in an image forming apparatus main body due to occurrence of a jam.

  Some conventional image forming apparatuses include a plurality of sheet storage units so that an image can be formed on various sheets such as sizes and materials. In such an image forming apparatus, the first image is formed after the image forming operation is started. In order to shorten the time until the formed sheet is output, the sheet storage unit is arranged near the image forming unit. Further, there is a sheet storage unit having a large capacity so that the image forming operation can be continued without supplying the sheet for a long time.

  However, since there is usually only one sheet conveyance path for feeding sheets fed from the plurality of sheet storage units to the transfer unit for transferring the toner image, a plurality of sheets fed from the plurality of sheet storage units are used. Most apparatuses have a configuration in which a sheet is joined to a sheet conveyance path for feeding a sheet to a transfer unit via any one of the sheet conveyance paths.

  On the other hand, in the case of forming a color image in a conventional image forming apparatus, for example, there is one provided with a plurality of fixing units in order to improve image quality. A fixing conveyance path for selectively passing through one or a plurality of fixing units is provided (see Patent Document 1).

  However, in such a conventional image forming apparatus, the sheet conveyance path in the apparatus is large-scale and complicated, and therefore, it stays in the apparatus when an abnormality such as a jam occurs in the apparatus. Improving the jam handling property of the sheet being used has become an important issue.

  Therefore, for example, in order to solve this problem, even if a jam occurs, image formation is continued as much as possible to minimize the waste of the sheet, and in order to simplify the jam processing operation, the sheet is moved to the door. There is a configuration in which jamming by a user can be easily performed by transporting to a position of a unit to be opened and closed and then stopping. In addition, after the jam processing by the user, there is a configuration in which the sheets staying in the apparatus are discharged without annoying the user's hand by the automatic discharge mode (see Patent Document 2).

JP 2003-5545 A JP-A-62-85261

  However, in such a conventional image forming apparatus, when the sheet is transported to a predetermined position of the door or the opening / closing unit and then stopped, the positional relationship between the sheets is different from that when the sheet is normally transported. When trying to automatically carry out the sheets staying in the plurality of sheet conveying paths, the sheets conveyed from the respective sheet conveying paths collide with each other at a merging portion downstream of each sheet conveying path, or at a predetermined position. May cause a rear-end collision and cause a jam again.

  Therefore, the present invention has been made in view of such a current situation, and when an abnormality such as a jam of a sheet occurs, the sheet is placed in a predetermined position without causing another jam or causing damage. It is an object of the present invention to provide an image forming apparatus that can be transported and discharged from the apparatus.

  The present invention includes a plurality of sheet conveyance paths having a merging portion on the downstream side in the sheet conveyance direction, and selectively determines a sheet conveyance path from the plurality of sheet conveyance paths according to an image forming mode and conveys the sheet. In the image forming apparatus, an abnormality detecting unit that detects that an abnormality has occurred in the image forming apparatus body, and a sheet that stays in the image forming apparatus body when the abnormality detecting unit detects the occurrence of an abnormality And a control unit that sequentially conveys the plurality of sheet conveyance paths based on the priority order.

  The present invention further includes a first fixing unit that fixes the toner image transferred to the sheet, and a second fixing unit provided downstream of the first fixing unit, wherein the first fixing unit includes the first fixing unit. In the image forming apparatus that selectively passes a passed sheet through the second fixing unit, a first sheet conveyance path through which the sheet that has passed through the first fixing unit passes, and the second fixing unit are disposed. And the second sheet conveyance path branched from the first sheet conveyance path through which the sheet that has passed through the first fixing unit selectively passes, and the occurrence of a jam in the image forming apparatus main body is detected. Jam detecting means, and when the jam detecting means detects occurrence of a jam, at least one of the sheets staying in the first and second sheet transport paths is retained in the second sheet transport path. Giving priority to the seat And control means for controlling so as to discharge the confluent portion of the second sheet conveying path, and further comprising a.

  As in the present invention, when the abnormality detection means detects the occurrence of an abnormality, among the sheets staying in a plurality of sheet conveying paths having a merging portion on the downstream side in the sheet conveying direction, the merging unit based on the priority order By controlling to sequentially convey the sheet toward the sheet, it is possible to convey the sheet without causing jamming of the sheet and without causing damage.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes an image forming apparatus, and 2 denotes an image forming apparatus main body (hereinafter referred to as an apparatus main body). The apparatus main body 2 includes a first chassis unit 2A and a second chassis unit 2B. Reference numeral 3A denotes an image forming unit. The image forming unit 3A includes a photosensitive drum 3, a developing device 4 that visualizes the latent image formed on the photosensitive drum by attaching a toner, and image information to the photosensitive drum 3. An exposure unit 5 and the like for exposing and forming a latent image are provided.

  Reference numeral 6 denotes a hopper that replenishes the developing device 4 with toner, and reference numeral 7 denotes a transfer roller as transfer means for transferring a toner image visualized on the photosensitive drum to a sheet (recording medium). Further, 9 is a sheet feeding unit that feeds the sheet, 10 is a first conveying belt unit that conveys the transferred sheet to the second chassis unit side, and 11 is a toner image transferred on the first chassis unit side. This is a second conveyance belt unit that conveys a sheet on which an unfixed image is placed to the second chassis unit side.

  Reference numeral 12 denotes a first fixing device constituting a first fixing unit for fixing the toner image transferred in the first chassis unit on the sheet, and 15 is provided downstream of the first fixing device 12. This is a second fixing device that constitutes a second fixing unit for achieving the above.

  Reference numeral 500 denotes an external discharge path for discharging a sheet on which image formation has been completed to the outside of the apparatus, 16 is a refeed conveyance path for guiding a sheet to be re-fed during double-sided recording, and 503 is the first fixing device 12. This is a fixing conveyance path which is a first sheet conveyance path for sending the passed sheet to the outer paper discharge path 500. Further, reference numeral 502 denotes a bypass conveyance path which is a second sheet conveyance path branched from the fixing conveyance path 503 and the reverse fixing discharge path 501 for inverting the front and back of the discharged sheet. , 505 is a double-sided conveyance path for conveying the reversed sheet to the transfer roller 7, and 510 is a reverse path for reversing the sheet and conveying it to the double-sided conveyance path 505.

  When a sheet having an image formed on only one side is discharged, the sheet is discharged directly from the outer discharge path 500 with the image surface facing upward, and sent to the reverse discharge path 501 for switchback. And a mode in which the image is discharged with the image surface facing downward. When images are formed on both sides, the sheet on which the image is formed on one side is reversed with the reverse path 510 and sent again to the image forming unit via the double-sided conveyance path 505, and the other side of the sheet Then, image formation is performed.

  In addition, 8 is an exhaust device that exhausts the inside of the first chassis using a fan (not shown), 13 is an exhaust duct that mainly exhausts heat from the first and second fixing devices 12 and 15 in the second chassis unit, 21 is a caster.

  FIG. 2 is a control block diagram of the image forming apparatus 1 in the present embodiment. In FIG. 2, 201 is a CPU that performs basic control of the apparatus body 2. The CPU 201 includes a ROM 206 in which a control program is written, a RAM 205 for performing processing, an image processing unit 170 for processing image signals, an image memory unit 130 for storing processed images, and an external device (not shown). A communication IF 207 for performing a signal is connected. A part of the RAM 205 is a backup RAM in which data is not erased even when the power is turned off.

  Further, an input / output port 204 is connected to the CPU 201 via an address bus and a data bus. The input / output port 204 is connected to various load devices such as a motor and a clutch, and an input device such as a sensor for detecting the position of the seat. The CPU 201 inputs according to the contents of the control program in the ROM 206. Image formation processing is executed by sequentially controlling input / output via the output port 204.

  An operation unit 203 is connected to the CPU 201. As shown in FIG. 3, the operation unit 203 includes a numeric keypad 3002 that is a key for inputting a number, a start key 3003 for starting a copying operation, an operating state of the image forming apparatus 1, and a user. Display section 3001 for displaying various messages such as work instructions, work procedures, and the like. Note that the surface of the display unit 3001 is constituted by a touch panel, and works as a selection key by touching the surface.

  The CPU 201 controls the display unit 3001 and the numeric keypad 3002 of the operation unit 203. As a result, the user instructs the CPU 201 to change the image forming operation mode and display through the display unit 3001 and the numeric keypad 3002, and the CPU 201 operates the operation state of the apparatus main body 2 on the display unit 3001 and the operation set by the numeric keypad 3002. Displays the mode.

  FIG. 4 is a schematic diagram illustrating a sheet conveyance path of the image forming apparatus 1 according to the present embodiment. In the present embodiment, the sheet conveyance path in the image forming apparatus includes the above-described external paper discharge path 500 and reverse. In addition to the paper discharge path 501, the bypass conveyance path 502, the fixing conveyance path 503, and the double-side conveyance path 505, the main conveyance path 504, the right deck sheet feed path 506, and the left deck sheet feed path 507 are divided.

  As shown in FIG. 5, the apparatus main body 2 includes a paper discharge unit 550, a duplex path (left) unit 551, a duplex path (center) unit 552, a duplex path (right) unit 553, a vertical path unit 554, a horizontal path. Eleven of the pass unit 555, the pre-fixing transport unit 556, the first fixing unit 557 including the first fixing device 12, the upper fixing transport unit 558, the lower fixing transport unit 559, and the second fixing unit 560 including the second fixing device 15. The unit is provided so that it can be pulled out.

  Then, when a sheet jam occurs, the jam processing is performed by pulling out the unit in which the jammed sheet exists among these units 550 to 560. In this embodiment, when the CPU 201 detects a jam of a sheet by a detection unit (not shown), the CPU 201 does not stop the conveyance of the sheet immediately, but precedes the jammed sheet or the jammed sheet. The sheet is transported from the position when the jam occurs among the units 550 to 560 to the unit positioned on the downstream side, and then stopped.

  As a result, when a jammed sheet or a sheet preceding a jammed sheet is taken out, even if the corresponding unit is pulled out, these sheets are sandwiched between this unit and other adjacent units and are damaged. Can be prevented.

  Next, the sheet stop control operation when a jam occurs in the image forming apparatus 1 will be described with reference to the flowchart of FIG.

  When the CPU 201 detects the occurrence of a jam by a jam detection means (abnormality detection means) (not shown) such as a timer or a sensor, it first determines whether all the sheets are stopped (S601), and all the sheets are stopped. If it is confirmed that the sheet is not present (N in S601), it is next determined whether or not a sheet exists in the fixing unit (first and second fixing devices) (S610). Here, if there is a sheet in the fixing unit (Y in S610), if the sheet is stopped at that position, the sheet may be damaged by curling or the like due to heat or pressure from the fixing unit. The conveyance of the sheet is continued for the time until the toner passes through the fixing unit. In other words, it waits until the conveyance of the sheet is stopped until the sheet passes through the fixing unit (fixing unit passing time wait) (S611).

  On the other hand, if no sheet is present in the fixing unit (N in S610), it is next determined whether or not a sheet is present in the junctions J1 to J4 of the sheet conveyance path shown in FIG. 4 (S620). Here, when a sheet is present in the merging portions J1 to J4 (Y in S620), in order to prevent the sheet from blocking the merging portions J1 to J4 in the automatic discharge mode described later, the sheets are joined. The conveyance of the sheet is continued for the time until it passes J4. In other words, it waits for the sheet to stop being conveyed until the time for which the sheet passes through the joining portion (joining portion passage time wait) (S621).

  Next, when there is no sheet at the junction (N in S620), it is determined whether or not the sheet spans between units that are opened and closed by the user during jam processing (step S630). Here, if the sheet is straddling between the units (Y in S630), the sheet trailing edge is in the sheet conveying direction so that the sheet is not folded or torn during the jam processing by the user and the jam handling performance is not deteriorated. The conveyance of the sheet is continued for the time until it exits the upstream unit. That is, it waits for the conveyance of the sheet to stop for the time when the sheet leaves the unit (unit removal time wait) (S631).

  Next, when there is no sheet in the fixing unit and the junctions J1 to J4 and there is no sheet straddling between the units (N in S630), the motor that transports the sheet to be stopped is stopped. (S640) to stop the sheet. Then, after performing these processes on all the sheets existing in the image forming apparatus, if it can be confirmed that the stop of all the sheets is completed (Y in S601), the jam stop process is terminated. It has become.

  By the way, when a jam occurs in this way, after the sheet is stopped, the jam processing by the user is performed, and thereafter, the sheet staying in the apparatus is ejected without bothering the user. However, in the present embodiment, the control of the automatic discharge mode after the jam stop is performed according to the priority table of the sheet conveyance path for each image forming mode shown in Table 1 below.

  Here, the priority order in the priority table of the sheet conveyance path is determined as follows. The priority described below is higher as the numerical value is larger, and the priority is lower as the numerical value is smaller. Priority 7 is the highest priority, and priority 1 is the lowest priority. Further, this priority order table is stored in, for example, the RAM 205 or the like.

  In the automatic discharge mode, since it is necessary to discharge the sheets sequentially from the downstream side in the sheet conveyance direction in the apparatus, the priority for discharging the sheets is first out of the sheet conveyance paths shown in FIG. The paper discharge path 500 or the reverse paper discharge path 501 has a high priority.

  In particular, the outer discharge path 500 is positioned in the vicinity of the second fixing device 15 and is therefore given the highest priority in order not to damage the stopped sheet. Since the sheet is discharged to the outside of the apparatus via 501, it is necessary to first discharge the sheet staying in the reverse discharge path 501 first to the outside of the apparatus.

  The reverse discharge path 501 is not used in the single-sided mode and is used in the double-sided mode, but there is no sheet to be discharged out of the apparatus, so that no sheet stays in the discharge unit.

  From the above, the priority is determined as follows.

1. For single-sided mode and double-sided mode: Priority 7 is the outer discharge path 500
2. In reverse mode: Priority 7 is reverse paper discharge path 501
Priority 6 is the external discharge path 500

  Next, priorities of the bypass conveyance path 502 and the fixing conveyance path 503 positioned upstream of the outer paper discharge path 500 are determined. Since the second fixing device 15 exists in the bypass conveyance path 502, the sheet is damaged. The possibility of giving is higher than that of the fixing conveyance path 503. It is also clear that the main transport path 504 that is the branching source of the bypass transport path 502 and the fixing transport path 503 has the second highest priority regardless of the operation mode.

  Therefore, the next priority is determined regardless of the operation mode.

1. In single-side mode and double-side mode: priority 6 is bypass conveyance path 502
: Priority 5 is fixing conveyance path 503
: Priority 4 is main transport path 504
2. In reverse mode: Priority 5 is bypass conveyance path 502
: Priority 4 is fixing conveyance path 503
: Priority 3 is main transport path 504

  Next, it is used when operating in the double-sided mode, or when operating in the single-sided mode or the reverse mode, and feeding the sheet using the left deck paper feed path 507. The double-sided conveyance path 505 is set as the next priority. Next to the double-sided conveyance path 505, the reverse discharge path 501 in which the sheet stays only in the double-sided mode as described below, and finally the right side where the sheet was fed regardless of the operation mode. The priority of the deck sheet feed path 506 or the left deck sheet feed path 507 is determined, and the priority of the final sheet conveyance path unit is determined.

1. In single-sided mode: Priority 3 is double-sided conveyance path 505
: Priority 2 is right or left deck paper feed path 506/507
2. In reverse mode: Priority 2 is duplex transport path 505
: Priority 1 is right or left deck paper feed path 506/507
In duplex mode: Priority 3 is duplex transport path 505
: Priority 2 is reverse paper discharge path 501
: Priority 1 is right or left deck paper feed path 506/507

  In this embodiment, the priority of the sheet conveyance path unit is determined as described above, but this priority determination is basic, for example, right deck feed path in single-side mode or reverse mode. Needless to say, if only 506 is used, the right deck paper feed path 506 may be determined as the next priority of the main transport path 504.

  Further, when controlling to selectively pass the first fixing device 12 and the second fixing device 15 according to the type of sheet and the operation mode, for example, in the case of thin paper or plain paper, only the first fixing device 12 passes. In the cardboard single-sided / reversal mode, the bypass transport path 502 and the fixing transport path 503 that are not used are excluded from the target by processing for determining the priority of each mode, such as when the second fixing device 15 is always passed. Needless to say, it can be excluded.

  When the jam detection unit detects that a jam has occurred in the image forming apparatus main body, the sheet staying in the image forming apparatus main body is stopped, and the stopped sheet is discharged based on a predetermined priority order. In the automatic discharge mode, the CPU 201 serving as the control unit automatically discharges the sheet using the priority order table determined in this way.

  Next, the automatic discharge mode control operation in the image forming apparatus 1 using the priority order table determined as described above will be described with reference to the flowchart of FIG.

  First, the CPU 201 acquires a priority order table corresponding to the mode when performing the automatic discharge mode shown in Table 1 determined from the priority determination process described above from the RAM 205 (S700), and thereafter, other than the jammed sheet. In order to discharge the preceding sheet to the outside of the image forming apparatus, driving of the motor of the sheet discharge unit is started (S701), and preparations for starting the automatic discharge mode are started.

  Next, automatic discharge is performed based on the priority order of the acquired priority order table. Here, it is determined whether or not the acquired priority table has ended (S702). If the priority table has not ended (N in S702), it is selected according to the priority of the priority table. Driving of the motor in the sheet conveyance path is started, and discharging of the sheets staying in the sheet conveyance path is started (S703).

  Next, the discharging operation is continued for a time corresponding to the path length of the selected sheet conveyance path (S704). Thereby, the sheet is discharged. Then, after the sheet is discharged in this way, the driving of the motor in the sheet conveyance path is stopped, thereby completing the automatic discharge operation of one sheet conveyance path (S705).

  Next, when the automatic discharge operation of one sheet conveyance path is completed as described above, the next sheet conveyance path to be automatically discharged is selected from the priority table (S706), and automatic discharge of the selected sheet conveyance path is started. . Then, this operation is performed until the priority table ends, and when the priority table ends (Y in S702), the driving of the motor of the paper discharge unit is stopped and the automatic discharge mode is ended.

  In this way, by giving priority to a plurality of sheet conveyance paths having the merging portion and discharging the sheet in the automatic discharge mode after the jam processing based on the priority, the sheet is jammed again at the merging portion. Therefore, it is possible to realize the image forming apparatus 1 that is reliable and has excellent jam processing performance.

  Further, in the automatic paper discharge mode, the CPU 201 gives priority to the sheets staying in the bypass transport path 502 among the sheets staying in the fixing transport path 503 and the bypass transport path 502 at least. By controlling to discharge to the junction portion J4 (see FIG. 4) of the bypass conveyance path 502, the sheet can be discharged without damaging the sheet and without causing a jam again.

  In other words, among the sheets staying in a plurality of sheet conveyance paths having a merging portion on the downstream side in the sheet conveyance direction, priority is given to the sheet stopped in the downstream sheet conveyance path according to the image forming mode. By controlling so that the sheet is sequentially discharged toward the joining portion, when an abnormality such as a sheet jam occurs, the sheet can be discharged without causing another jam or causing damage.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a control block diagram of the image forming apparatus. FIG. 3 is a plan view of an operation unit of the image forming apparatus. FIG. 3 is a schematic diagram illustrating a sheet conveyance path of the image forming apparatus. FIG. 3 is a diagram illustrating a position of a unit provided in the image forming apparatus so as to be able to be pulled out. 6 is a flowchart illustrating a sheet stop control operation when a jam occurs in the image forming apparatus. 6 is a flowchart showing an automatic discharge mode control operation of the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 3A Image forming part 12 1st fixing apparatus 15 2nd fixing apparatus 201 CPU
205 RAM
500 Outer discharge path 501 Reverse discharge path 502 Bypass transport path 503 Fixing transport path 505 Duplex transport path 504 Main transport path 506 Right deck paper feed path 507 Left deck paper feed path 550 Paper discharge unit 551 Duplex path (left) unit 552 Double-sided pass (center) unit 553 Double-sided pass (right) unit 554 Vertical pass unit 555 Horizontal pass unit 556 Pre-fixing transport unit 557 First fixing unit 558 Upper fixing transport unit 559 Lower fixing transport unit 560 Second fixing unit

Claims (8)

In an image forming apparatus that includes a plurality of sheet conveyance paths having a merging portion on the downstream side in the sheet conveyance direction, selectively determines a sheet conveyance path from the plurality of sheet conveyance paths according to an image forming mode, and conveys the sheet ,
An abnormality detection means for detecting that an abnormality has occurred in the image forming apparatus main body;
Control means for conveying sheets staying in the image forming apparatus main body in order from the plurality of sheet conveying paths based on a predetermined priority when the abnormality detecting means detects the occurrence of abnormality;
An image forming apparatus comprising:   When the abnormality detection unit detects an abnormality and the image forming operation cannot be continued normally, the control unit stops the sheet remaining in the image forming apparatus at a stoppable position on the sheet conveyance path. The image forming apparatus according to claim 1.   The abnormality detection unit detects a jam of the sheet, and a unit unit for removing the jammed sheet is provided in the image forming apparatus main body so that the unit can be pulled out, and when the control unit stops the sheet, The image forming apparatus according to claim 2, wherein the sheet is stopped at a position where the sheet is pulled out integrally with the unit portion.   The control unit stops the sheet staying in the image forming apparatus main body when the abnormality detection unit detects the occurrence of the abnormality, and discharges the stopped sheet based on a predetermined priority. The image forming apparatus according to any one of claims 1 to 3. A first fixing unit that fixes the toner image transferred to the sheet; and a second fixing unit that is provided downstream of the first fixing unit, and selects a sheet that has passed through the first fixing unit. In an image forming apparatus that passes through the second fixing unit,
A first sheet conveyance path through which a sheet that has passed through the first fixing unit passes;
A second sheet conveyance path branched from the first sheet conveyance path in which the second fixing unit is arranged and a sheet that has passed through the first fixing unit selectively passes;
Jam detecting means for detecting the occurrence of jam in the image forming apparatus main body;
When the jam detection means detects the occurrence of a jam, priority is given to a sheet staying in the second sheet transport path among at least the sheets staying in the first and second sheet transport paths. Control means for controlling discharge to the joining portion of the first and second sheet conveying paths;
An image forming apparatus comprising:   When the jam detection unit detects the occurrence of a jam, the control unit stops the sheet staying in the image forming apparatus main body, and discharges the stopped sheet based on a predetermined priority. The image forming apparatus according to claim 5.   The image forming apparatus according to claim 5, wherein the control unit performs a stop position control of the sheet so that the sheet does not stop in the first and second fixing units. The control means preferentially discharges the sheet on the downstream side of the joining portion of the first and second sheet conveyance paths before discharging the sheet staying in the second sheet conveyance path. The image forming apparatus according to claim 5, wherein the image forming apparatus is an image forming apparatus.

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