JP3715730B2 - Sheet material conveying mechanism and image recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet material conveying mechanism provided with a curl correcting means that corrects curl of a sheet material and stabilizes subsequent stackability, transportability, and the like, and a printer, a copying machine, a facsimile, and the like using the same. The present invention relates to an image recording apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is an electrophotographic printer that discharges a sheet material conveyance path as viewed from the side in an S-shape or U-shape, with a printing surface on a stacking tray. In this case, as the curling correction means for the recording sheet material that has passed through the fixing device and becomes curled, the curvature of the sheet material conveyance path after fixing is set on the side opposite to the curl direction, and curling is performed simultaneously with conveyance. There was a way to correct.
[0003]
However, if the curl cannot be corrected by the curvature of the sheet material conveyance path after fixing alone, or the curvature of the sheet material conveyance path after fixing must be set in the direction of increasing the curl in reverse due to the convenience of the device. There was a case. In this case, a decurling roller pair is provided in the vicinity of the downstream paper discharge port, and the curl is corrected by the decurling roller pair, and then discharged onto the stacking tray (face-down tray).
[0004]
In addition, after fixing, there is a sheet material that is discharged to the stacking tray (face-up tray) without discharging the sheet material to the curvature conveyance path, and is discharged to the rear as it is, with the printing surface facing up.
[0005]
In this case, a curl removing roller pair is provided in the vicinity of the downstream side of the fixing device to correct the curling of the sheet material discharged to the face-up tray. Further, the corrected sheet material discharged from the face-up port may be taken into the reversing part of the double-sided device.
[0006]
Further, there has been a method of correcting the curl by pulling both ends of the curled sheet material between the conveyance rollers immediately downstream from the fixing roller or between the conveyance rollers adjacent in the downstream.
[0007]
Alternatively, as described above, there is a method in which the curl correcting force is increased by cooling the sheet material with a fan immediately after correcting the curl.
[0008]
[Problems to be solved by the invention]
However, in the above-described conventional example, the amount of curl correction is uniform, and adjustment is impossible, or even if adjustment is possible, the adjustment amount is small. On the other hand, since the curl correction amount is adjusted to a sheet material that is frequently used, the sheet material in a specific state has the following problems.
[0009]
For example, a sheet material in which the direction of the sheet material is perpendicular to the traveling direction has a large amount of curling after fixing, and this tendency is particularly strong in recycled paper in a hygroscopic state, and may be rounded.
[0010]
Therefore, in the case of such a sheet material, even after passing through the curl removal roller, curling is not corrected, and the sheet material is curled and discharged on the stacking tray, or the sheet material stacked on the stacking tray is extruded. Sometimes happened.
[0011]
In order to increase the curl correction force on the sheet material in a specific state, the nip pressure at the decurling roller portion can be increased or the radius of curvature of the nip portion of the decurling roller can be increased. It is possible to make it variable so that it can be made smaller.
But,
(1) The adjustment mechanism becomes complicated and added, so that the apparatus becomes large. (2) The adjustment mechanism becomes complicated and added, resulting in an increase in cost.
(3) In order to increase the load on the drive source, the drive current must be increased,
For this reason, no actual countermeasures are taken, and the above-described round discharge and extrusion discharge on the stacking tray of the specific-state sheet material are often unavoidable and often dealt with.
[0012]
On the other hand, although the curl correction amount can be adjusted by rotating / non-rotating the fan, (1) the adjustment amount is small and the curl in a curled state cannot be handled.
(2) The cost increase, including cables, can reach several hundred yen by adding fans.
(3) No measures are actually taken for the reason that the device becomes larger because the occupied area is required due to the additional fan.
[0013]
Further, even if the sheet material is not pulled, the curl correction amount can be adjusted only by changing the sequence without increasing the cost. However, the adjustment amount is small and the curling state cannot be dealt with.
[0014]
In some cases, the sheet material is taken into the double-sided device after fixing the first side, reversed, and then returned to the printer body to perform the second side printing.
[0015]
In this case, the curl is first corrected by a decurling roller in the vicinity after fixing. However, when the sheet material is in a hygroscopic state as described above, the curl is not sufficiently corrected. As a result, due to the residual curl, the tip may be caught on the transport path, causing corner breakage or jamming in the apparatus.
[0016]
On the other hand, there is only a method for reducing the curling amount at the generation source by lowering the fixing temperature control than in the single-sided printing mode. However, as an adverse effect, the fixability at low temperatures is often sacrificed.
[0017]
Further, when the decurling roller cannot be set in the vicinity of the fixing device due to the space on the printer main body side, cost, paper handling, etc., the fixing temperature control must be further lowered. Therefore, the sacrifice of fixability had to become more serious.
[0018]
An object of the present invention is to solve the problems of the conventional example.
[0019]
That is,
The object of the first invention according to the present application is to provide a sheet material transport mechanism that can adjust the curl correction force in a direction that dramatically increases the curl correction force by an inexpensive configuration. .
[0020]
The object of the second invention according to the present application is to simplify the sequence and make it possible to adjust the curl correction force in the direction corresponding to the second aspect.
[0021]
The object of the third invention according to the present application is to make it possible to adjust the curl correction force in a direction to further increase, corresponding to claim 3.
[0022]
According to a fourth aspect of the present application, in correspondence with claim 4, it is possible to adjust not only the direction in which the curl correction force is further increased, but also the direction in which the curl correction force is decreased. The object of the fifth invention according to the present application is to further increase the curl correction range in correspondence with claim 5.
[0023]
According to a sixth object of the present application, corresponding to claim 6, it is possible to adjust not only the direction in which the curl correction force is further increased, but also the direction in which the curl correction force is decreased with an inexpensive configuration.
[0024]
The object of the seventh invention according to the present application is to increase physical distribution efficiency in correspondence with claim 7.
[0025]
The eighth object according to the present application is to further increase the distribution efficiency in response to claim 8.
[0026]
An object of a ninth invention according to the present application is to reduce the cost of a dedicated conveyance path in correspondence with claim 9.
[0027]
The object of the tenth aspect of the present application is to make it possible to adjust the curl correction force further in the direction of further increasing by the cooling effect and to prevent the temperature inside the apparatus from rising, corresponding to claim 10. .
[0028]
The object of the eleventh aspect of the present application is to expand the specification of media discharged to the stacking tray in correspondence with claim 11.
[0029]
The object of the twelfth aspect of the present application is to expand the media specification capable of duplex printing without sacrificing the fixing property, corresponding to claim 12.
[0030]
In addition, even when the double-sided device is mounted, the paper handling property is improved by using the face-up tray.
[0031]
The object of the thirteenth aspect of the present application is to expand the media specification applicable to the sorter in correspondence with claim 13.
[0032]
According to a fourteenth aspect of the present application, in correspondence with claim 14, the curl correction condition is adjusted manually from the operation unit, and the media specification is further expanded.
[0033]
The object of the fifteenth aspect of the present invention is to adjust the curl correction condition by an inexpensive means corresponding to claim 15.
[0034]
The object of the sixteenth aspect of the present application is to automatically adjust the curl correcting means in correspondence with claim 16.
[0035]
The object of the seventeenth aspect of the present application is to reduce curling when the power is turned on in the on-demand fixing device, corresponding to claim 22.
[0036]
[Means for Solving the Problems]
  The present invention is a sheet material transport mechanism having the following configuration.
  (1) A curl correcting unit that corrects a curled sheet material, and a sheet material conveying path including the curl correcting unit at a predetermined switching position to switch the sheet material conveying direction to the curl correcting unit. Pass multiple timesDo the actionA drive unit that enables the switching of the sheet material in accordance with the curl characteristics of the sheet material, and a switching condition that can be set according to the curling characteristic of the sheet material, and the driving unit is driven based on the switching condition. Means for adjusting the curl correction force on the sheet material by(I) The switching condition can be set as the number of times of switching during the operation of passing the sheet material through the curl correction means a plurality of times, and the means for adjusting the curl correction force can be set at the set number of times of switching. The driving means is driven so as to switch the conveyance direction of the material, or (ii) as the switching condition, a switching distance that is a distance to convey the sheet material after switching the conveyance direction of the sheet material can be set. The means for adjusting the curl correction force drives the driving means so as to switch the conveyance direction of the sheet material at a set switching distance.It is characterized by that.
[0037]
As described above, the sheet material can pass through the curl correcting means a plurality of times by switching the conveyance direction. Therefore, the curl correction force can be adjusted in the increasing direction.
(2) In order to switch the conveyance direction of the sheet material, a detection means for detecting a switching position is provided.
[0038]
The switching position is determined, for example, by detecting the sheet material edge position. By providing a detection means, when the number of corresponding sheet materials increases or the number of optional paper feed ports increases, There is no need to set the reverse timing for each paper slot.
(3) The present invention is characterized by having a dedicated conveying path that branches from the sheet material conveying path as a conveying path when the sheet material conveying direction is switched.
[0039]
By providing a dedicated conveyance path that increases the curl correction direction of the curl correction means, the curl correction force can be adjusted in a further increasing direction.
(4) A direction changing means for guiding the sheet material from the sheet material conveyance path to the dedicated conveyance path is provided.
[0040]
In addition to increasing the curl correction direction of the curl correction means, it is possible to provide a dedicated conveyance path in the direction of reduction. Therefore, the curl correction force can be adjusted not only in the direction of further increasing but also in the direction of decreasing.
(5) The direction changing means is a guide that can swing around a fixed point.
[0041]
Since the dedicated conveyance path can be provided in various ways, it is possible to further increase the curl correction range.
(6) The direction changing means is provided so as to obliquely block the sheet material conveying path until it is first guided to the curl correcting means, and forms a part of the dedicated conveying path and has a guide member having elasticity. It is characterized by being.
[0042]
When the direction is changed, an actuator such as a solenoid is not required. Therefore, the curl correction force can be adjusted not only in a direction to be further increased, but also in a direction in which the curl correction force is reduced.
(7) The exclusive conveyance path is removable.
Since the sheet material conveyance path is provided exclusively, the volume of the apparatus becomes larger than the case where it is not provided exclusively. Here, if the configuration is removable during transportation, the packaging volume can be reduced.
(8) The exclusive conveyance path can be stored.
[0043]
It is possible to save the trouble of removing the dedicated conveyance path during transportation.
(9) The dedicated conveyance path is a part of another apparatus main body adjacent to the sheet material conveyance mechanism main body.
[0044]
By using a part of another adjacent apparatus main body, it is possible to reduce an area that must be newly set as a dedicated conveyance path.
(10) The sheet material conveyance mechanism according to any one of (2) to (6), wherein the sheet material is exposed in the dedicated conveyance path.
[0045]
For example, the sheet material heated by the fixing device is cooled because it jumps out of the apparatus and touches the outside air during curl correction.
(11) The sheet material is guided to the stacking unit after the sheet material conveyance direction switching operation is completed.
[0046]
It is possible to expand the specifications of media discharged to the stacking unit.
(12) The sheet material is guided to a double-sided apparatus after the sheet material conveyance direction switching operation is completed.
[0047]
It is possible to increase the curl correction power without lowering the fixing temperature.
[0048]
  The position of the curl correction means can be set at a position away from the fixing device.
  In addition, after the sheet material conveyance direction switching operation is completed, the sheet material is further guided to the reverse conveyance unit on the downstream side in the conveyance direction
The reversing conveyance unit is
Curl correction means for correcting the curled sheet material;
A driving means that enables the sheet material to be passed through the curl correcting means a plurality of times by switching the conveying direction of the sheet material at a predetermined switching position of the sheet material conveying path including the curl correcting means;
According to the curl characteristic of the sheet material, a switching condition at the time of the conveyance direction switching operation of the sheet material is settable, and means for adjusting the curl correction force on the sheet material;
Is further provided.
  (13) The sheet material is guided to a sorter after completion of the operation of changing the conveying direction of the sheet material.
[0049]
  It is possible to expand the specifications of the media discharged to the sorter.
  The switching condition is at least one of a switching direction, a sheet material conveying speed, a switching distance, and the number of times of switching in the sheet material conveying direction switching operation, and is previously set according to the curl characteristics of the sheet material. It is characterized by being set.
  (14)The switching condition is:Switching direction, sheet material transport speed, switching distance, cutting during sheet material transport direction switching operationReplacementNumber of timesAt least one of the conditions,It is characterized in that it is manually changed from the operation unit.
[0050]
  The switching condition is:The curl correction conditions can be changed manually.
  (15) Switching direction, sheet material conveyance speed, switching distance, switching during sheet material conveyance direction switching operationReplacementNumber of timesAt least one of the conditions,Cutting on the controller boardReplacementIt is characterized in that it is manually changed by a switch.
[0051]
  The curl correction conditions can be changed manually.
  (16)At least one of a curl amount detection sensor for detecting the curl amount of the sheet and a humidity sensor for detecting ambient humidity is provided.
  The curl amount detection sensor or the humidity sensorBased on detection information fromTheCutReplacementConditionsSelfIt is characterized by changing dynamically.
[0052]
  The curl correction conditions can be changed automatically..
[0053]
  The curl correction conditions can be changed according to the curl amount of the sheet material.The curl correction conditions can be changed according to the ambient temperature and humidity.
  Also,There is a heating unit that heats the sheet material upstream of the curl correction means in the sheet material conveyance direction.Provided,Temperature sensor for detecting temperature of the heating unitChange the switching condition automatically based on the detection information fromIt is characterized by that.
[0054]
  It is possible to change the curl correction conditions according to the temperature of the heating part.
[0055]
  Also,The curl correcting means is constituted by a pair of rollers having a nip portion having a curvature opposite to the curled state of the sheet material.
  Also,The curl correcting means is constituted by a conveyance path having a curvature shape opposite to the curled state of the sheet material.
  Also,On the upstream side of the curl correction means in the sheet material conveying direction, a heating means, a heat resistant film for transferring heat from the heating means contacting one surface to the other surface, the heat resistant film and the heat resistance A pressure unit that forms a nip portion by heat contact with the film, and heat fixing for heating and fixing the image on the recording material by holding and transporting the recording material carrying the unfixed image in the nip portion. A device is provided.
  Also,An image forming step is provided upstream of the curl correction means in the sheet material conveyance direction.
  Also,The drive means is a pulse motor.
[0056]
Since it is open-loop control, it is possible to make the reciprocating motion inexpensively and accurately.
[0057]
  The image recording apparatus of the present invention is configured as follows.
  ShiAn image recording unit for recording an image on a sheet material and a sheet material conveyance path provided with the sheet material conveyance mechanism are provided.Also,It has a fixing unit for fixing an unfixed image recorded by the image recording unit, and the sheet material conveying mechanism is provided in the sheet material conveying path downstream in the conveying direction of the fixing unit.
[0058]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a principle diagram of the present invention.
[0059]
The curl direction C1 of the sheet material S1 is set to a direction (downward) that curves downward in a concave shape before being guided to the decurling roller pair 1000 as a curl correction unit.
[0060]
The decurling roller pair 1000 is composed of driving rollers 1001 and 1002 that rotate in the left direction at parallel positions on the conveying path, and driven rollers 1003 that rotate in contact with each other at pressure positions above the driving rollers 1001 and 1002. Is done.
[0061]
Therefore, the nip shape at the pressure contact portion of the curl removing roller pair 1000 is a curvature shape that protrudes downward. As a result, since the sheet material S1 follows the nip shape when passing through the curl removing roller pair 1000, the curl tends to be corrected in an upwardly curved direction (upward).
[0062]
Further, when the rear end of the sheet material S1 reaches near the nip portion of the curl removing roller pair 1000, the driving source 2000 of the curl removing roller pair 1000 is reversed so that the rotation directions of the driving rollers 1001 and 1002 are reversed ( CW direction).
The reverse rotation timing is performed after a predetermined time t1 has elapsed so that the sheet material S1 starts to be conveyed from a sheet feeding position (not shown) and the rear end of the sheet material S1 reaches near the nip portion of the curl removing roller pair 1000. This timing may be after the rear end of the sheet material S1 passes through the nip portion of the curl removing roller pair 1000.
[0063]
When the drive source 2000 is reversed, the sheet material S1 is conveyed by changing the rear end so far to the front end.
[0064]
When a predetermined amount is conveyed, the direction is changed again and conveyed. This repeated operation is repeated.
[0065]
A flowchart and a timing chart showing a series of operation control are shown in detail in FIGS.
[0066]
It is determined whether or not the conveyance of the sheet material has been started based on the presence or absence of a print start signal or the like (step 2). When the start signal is read, the motor of the drive source 2000 starts driving (step 3). This driving direction is the forward rotation direction (CCW), and the motor CCW flag is set.
[0067]
When a predetermined time (t1) elapses after the motor starts rotating (step 4), it is determined whether or not the sheet material is a curl correction processing target (step 5), and the process ends if it is not a correction target.
[0068]
In the case of the sheet material to be processed, the curl correction length and the number of repetitions set in advance according to the sheet material are read (step 6), and the curl correction process is started (step 7). First, motor reverse drive is started and the motor CW flag is set (step 8). Next, it is determined whether or not a predetermined amount of back has been achieved corresponding to the curl correction length (step 9), and when the predetermined amount of back is reached, the forward rotation of the motor is started and the motor CCW flag is set (step 10).
[0069]
Next, it is determined whether or not the predetermined amount has been returned (step 11), and when the predetermined amount has been returned, it is determined whether or not the curl correction has been completed (step 12). This end determination is made based on, for example, whether or not a predetermined number of repetitions has been reached. If it has not been completed yet, the procedure returns to (Step 8) and the above procedure is repeated.
[0070]
As described above, the sheet material S1 passes through the curl removing roller pair 1000, which is a curl correcting unit, a plurality of times by switching the conveyance direction. Therefore, the curl correction force can be adjusted in the increasing direction.
[0071]
FIG. 4 is a principle diagram in the case of using a substantially curved conveyance path 1010 as the curl correcting means.
[0072]
The curling direction of the sheet material S2 is set downward like the sheet material S1 before being guided to the conveyance path 1010. When the sheet material S2 passes through the conveyance path 1010 by the conveyance roller pair 1011 at the entrance of the conveyance path 1010, the sheet material S2 is forced to conform to the shape of the conveyance path 1010.
[0073]
On the other hand, since the conveyance path 1010 has a curved shape in a direction in which the path of the sheet material S2 is switched upward, the sheet material tends to be corrected in the upward curl direction during conveyance.
[0074]
The detection means 3001 at the entrance of the conveyance path 1010 detects the leading edge of the sheet material S2, advances the specified distance, and then reverses the drive source 2001 of the conveyance roller pair 1011. Then, by repeating this repetitive operation, the curl correction force can be adjusted in the increasing direction.
[0075]
A flowchart and a timing chart showing a series of operation control are shown in FIGS.
[0076]
First, it is determined whether or not the conveyance of the sheet material is started based on the presence or absence of a drive start signal such as a print start signal (step 2). When the start signal is read, the motor of the drive source 2001 starts driving (step 3). . This driving direction is the forward rotation direction (CCW), and the motor CCW flag is set.
[0077]
When the trailing end of the sheet material S2 is detected by the detection means 3001 (step 4), it is determined whether or not the sheet material is a curl correction processing target (step 5). In the case of the sheet material to be processed, the curl correction length and the number of repetitions set in advance according to the sheet material S2 are read (step 6), and the curl correction process is started (step 7).
[0078]
First, motor reverse drive is started and the motor CW flag is set (step 8). Next, it is determined whether or not a predetermined amount of back has been achieved corresponding to the curl correction length (step 9), and when the predetermined amount of back is reached, the forward rotation of the motor is started and the motor CCW flag is set (step 10). Next, it is determined whether or not the predetermined amount has been returned (step 11), and when the predetermined amount has been returned, it is determined whether or not the curl correction has been completed (step 11). This end determination is made based on, for example, whether or not a predetermined number of repetitions has been reached. If it has not been completed yet, the procedure returns to (Step 8) and the above procedure is repeated.
[0079]
As described above, by providing the detection means 3001 for detecting the sheet material edge position, when the types of the corresponding sheet material S2 increase or when the number of optional paper supply ports increases, each size or each paper supply port. It is not necessary to set the reverse rotation timing for each. Therefore, the sequence can be simplified and the curl correction force can be adjusted in the increasing direction.
[0080]
[First Embodiment]
FIG. 7 is a diagram showing a case where the present invention is applied to a double-sided device that is detachably provided as an option in a laser printer.
[0081]
This laser beam printer 100 can only form an image on only one side of the sheet material S with its own configuration, but a double-sided device 102 having a detachable sheet material reversing device 121 as shown in FIG. By attaching to 103, image formation can be performed on both sides of the sheet material S. Therefore, the laser beam printer 100 alone constitutes a single-sided image recording device, and the laser beam printer 100 and the double-sided device 102 together constitute a double-sided image recording device.
[0082]
In the laser printer 100, a video controller board (image signal creating means) 104 creates an image signal based on information transmitted from an external information device such as a personal computer or a word processor.
[0083]
Here, various electronic components installed on the video controller board 104 are not shown. The laser scanner 105 irradiates the photosensitive drum 106A rotating in the clockwise direction with the laser light L corresponding to the image signal created by the video controller board 104, and electrostatically sequentially applies to the photosensitive drum 106A. A latent image is formed.
[0084]
The electrostatic latent image formed on the photosensitive drum 106 </ b> A is successively visualized by toner supplied from a developing device (not shown) in the process unit 106 and conveyed to a transfer portion between the transfer roller 107. Is done.
[0085]
On the other hand, the sheet material S loaded and stored in the sheet feeding cassette 108 is sequentially fed from the uppermost sheet material one by one to the sheet feeding path 110 by the half-moon shaped sheet feeding roller 109 that rotates counterclockwise once. Then, it is conveyed by the conveying roller pair 111 to the registration roller pair 112 whose rotation is stopped.
[0086]
After the sheet material S that has reached the registration roller pair 112 hits the nip of the sheet material front end registration roller pair 112, the sheet material S is continuously conveyed until a predetermined loop is formed, and the skew state is corrected.
[0087]
After the correction of the skew state, the sheet material S is conveyed to the transfer section by the registration roller pair 112 that starts rotating at the timing of aligning with the toner image on the photosensitive drum 106A. As a result, the toner image on the photosensitive drum 106A is transferred onto the sheet material surface.
[0088]
After the transfer of the toner image, the sheet material S passes through the conveyance guide 113 and is conveyed to the fixing roller 114, where the transferred toner image is fixed on the sheet material surface.
When the laser beam printer 1 has been selected for the single-sided image forming mode, the sheet material S that has undergone the toner image fixing process is switched to the position 115A so that the tray discharge path 116 is reached. Then, the paper is discharged onto a paper discharge tray 117 at the top of the main body 103. At this time, the sheet material S is conveyed by a pair of conveying rollers 1181 and 1182 and discharged by a discharge roller 119.
[0089]
Further, when the laser printer 100 is selected in the double-sided image forming mode, the sheet material S that has been subjected to the toner image fixing process is switched to the reverse connection path 120 by switching the deflector 115 to the position 115B. It passes through the main body 103 and is discharged.
[0090]
Here, the sheet material S discharged out of the main body 103 is curled downward due to the characteristics of the fixing roller 114.
[0091]
Next, it is guided into the sheet material reversing device main body 121.
[0092]
First, the leading edge of the sheet material S is close to the upstream of the nip portion of the curl removing roller pair 123 and reaches the film-like guide 122.
[0093]
The guide 122 is attached so that the sheet material conveyance path has a wedge shape, and closes the path of the sheet material by the light elastic force of the film.
[0094]
The leading edge of the sheet material S advances following the guide 122, but when the leading edge 122A is reached, the sheet material conveying force overcomes the elastic force of the film and lifts the guide 122 slightly upward.
[0095]
Further, the sheet material S advances and is guided to a decurling roller pair 123 as a downstream curl correcting means.
[0096]
The decurling roller pair 123 is in contact with the driving rollers 123-1 and 123-2 that rotate in the left direction at the parallel positions on the conveyance path and the positions above the driving rollers 123-1 and 123-2. It comprises a driven roller 123-3 that rotates.
[0097]
Therefore, the nip shape at the pressure contact portion of the decurling roller pair 123 becomes a curvature shape protruding downward. As a result, the sheet material follows a nip shape when passing through the decurling roller pair 123, so that the curl tends to be corrected in the upward direction.
[0098]
When the rear end of the sheet material S passes through the front end 122A of the guide 122, the guide 122 again closes the sheet material conveyance path by the elastic force of the film. Further, when the rear end of the sheet material reaches near the nip portion of the curl removing roller pair 123, the drive source of the sheet material reversing device main body 121 is set so that the rotation directions of the drive rollers 123-1 and 123-2 are reversed. The pulse motor (not shown) is reversed.
[0099]
For the reverse rotation timing, the rear end of the sheet material S is first detected via the lever 1140 by a sensor such as a photo sensor (not shown) between the fixing roller 114 and the conveying roller pair 1181. Next, after the sheet material S has advanced by a designated pulse to reach the position near the upstream of the nip portion of the curl removing roller pair 123, the pulse motor is reversed.
[0100]
When the pulse motor rotates in the reverse direction, the sheet material S is conveyed by changing the rear end so far to the front end.
[0101]
The reverse conveyance path 124 is different from the conveyance path when the sheet material S advances forward on the front side of the curl removing roller pair 123. The reverse conveyance path 124 includes sheet material conveyance paths 124 </ b> A and 124 </ b> B that are inclined from the nip portion of the decurling roller pair 123 toward the printer main body 103.
[0102]
The sheet material S proceeds to the outside of the sheet material reversing apparatus main body 121 through the conveyance paths 124A and 124B.
[0103]
Further, the sheet material S advances along the inclined portion 125A of the conveyance guide 125 located downstream.
[0104]
The degree of inclination of the inclined portion 124A is set to be substantially the same as the degree of inclination of the conveyance path 122B so that the sheet material is stably conveyed at the connection portion with the upstream conveyance path 122B.
[0105]
After the sheet material S reverses the designated distance m, the rotation of the pulse motor, which is the drive source, is returned to the normal rotation direction again. After this switching operation is performed a plurality of times, it is forwardly rotated again and forwarded, and guided to the conveyance path 126 on the downstream side of the curl roller pair 123.
[0106]
Here, as described above, the conveyance direction of the sheet material S is switched in the curl removing roller pair 123 when the sheet material S in a specific situation is used and the heater temperature of the fixing device is equal to or higher than a certain temperature (T ° C.). Limited at times.
[0107]
The specific situation is, for example, the case of “lateral feeding” in which the sheet material S whose plow direction is perpendicular to the traveling direction is fed so that the short side is parallel to the traveling direction. In this case, it is known that the amount of curling after fixing increases. Furthermore, this tendency is strong when the sheet material S is in a hygroscopic state and the fixing temperature is high.
[0108]
That is, when the curl amount after fixing is large, the above-described repetitive sequence is used.
[0109]
Further, the sheet material conveyance speed, the reverse movement distance, and the number of reverse movements when the sheet material conveyance direction is switched are changed according to the curl characteristics of the sheet material S of each size.
Thereby, it is possible to optimize the curl correction force in each sheet material S.
[0110]
Here, regarding the size, the double-sided device 102 determines by receiving from the printer main body 103 a size signal corresponding to a combination of a plurality of commands (not shown) in the sheet material storage box 108.
[0111]
On the other hand, the fixing temperature is determined by receiving an output signal of a thermistor that detects the temperature of the fixing heater.
[0112]
FIG. 8 is a diagram illustrating a communication relationship between the duplex device 102 and the printer main body 100.
[0113]
First, the fixing temperature information Tf of the sheet material is notified from the main body control device 100A to the curl correction control unit 102A through the in-machine communication line S1. Next, the curl correction control unit 102A changes the curl correction condition based on the notified fixing temperature information Tf. The main body control device 100A is connected to the display / operation unit 100B through the communication line S2.
[0114]
A specific example of the curl correction condition is shown in FIG.
[0115]
FIG. 9A is a curl correction condition table example 1. FIG. That is, the sheet material is classified into the A series, the L series, and the other three types, and the A series is further divided into the A4 lateral feed size and the A3 size, and the L series is classified into LTR / Y and EXE. The conveyance distance, the number of repetitions, and the repetition speed are determined in advance for the high-temperature fixing temperature adjustment and the fixing temperature adjustment for a predetermined temperature or less.
[0116]
FIG. 9B shows a condition example in which the fixing temperature is further divided into three stages and the curl correction conditions are determined.
[0117]
Further, after making a large U-turn through the conveying roller pair 127 and the sheet material conveying path 128, the second decurling roller pair 129 is reached. The decurling roller pair 129 is positioned adjacent to the upper side of the driving roller 129-1 and the driving roller 129-1 that can rotate forward and backward, and the driven rollers 129-2 and 129 that rotate in contact with the driving roller 129-1. -3.
[0118]
Since the driving roller 129-1 rotates in the clockwise direction, when the leading end of the sheet material is nipped by the curl removing roller pair 129, the driving roller 129-1 is guided to the downstream conveyance path 142.
[0119]
The conveyance path 142 includes a conveyance guide 140 protruding rearward from the printer main body 103 and an upper surface 141A of the upper cover 141 of the sheet material storage box.
[0120]
Since the nip of the curl removing roller pair 129 has a curved shape with a bulge upward, correction is performed in the downward curl direction during nip conveyance.
[0121]
The reason for correcting in the lower curl direction is described. As described above, the sheet material in the lower curl state is corrected in the upper curl direction by the first curl roller pair 123 at the intake port of the reversing device main body 121. However, the downstream conveyance path 126 and the conveyance path 127 have a curved shape so as to return the curl to the original direction again. Accordingly, the purpose of the decurling roller pair 129 is to supplement this return.
[0122]
Further, the rear end of the sheet material is electrically detected by a photo interrupter (not shown) via the sensor lever 130 located on the downstream side of the sheet material conveyance path 128 and in front of the decurling roller pair 129. To do. After the detection, the specified number of pulses are input to the pulse motor of the drive source so that the trailing edge of the sheet material reaches the vicinity of the nip portion of the curl removing roller pair 129.
[0123]
Then, immediately after the input rotation for the designated pulse, the rotation direction of the pulse motor is switched to the opposite direction. Since the driving roller 129-1 rotates in the left direction, the sheet material performs a switchback motion, and enters the sheet material conveyance path 131 having a curved shape protruding in the depth direction (left direction in the drawing) of the reversing device main body 121. , Switch the course. At this time, the leading edge of the sheet material at the time of switchback is forcibly directed downward due to the nip shape of the decurling roller pair 129, and thus is easily guided to the conveyance path 131.
[0124]
Here, while the sheet material is reciprocated once by the curl removing roller pair 129, an action of correcting the curl downward is working.
[0125]
Further, the curvature shape of the sheet material conveyance path 131 works in a direction to further improve the curl correction effect in the curl removing roller pair 129 with respect to the sheet material being conveyed.
[0126]
The sheet passes through a conveyance roller 132 downstream of the sheet material conveyance path 131 and a sheet material conveyance path 133 further downstream, and is guided to a horizontal registration reference unit 144 that adjusts the registration in the horizontal direction.
[0127]
The lateral registration reference unit 144 is composed of a pair of skew feeding rollers 144A, 144B, and 144C provided obliquely with respect to the traveling direction. When the sheet material is conveyed by the pair of skew feeding rollers 144A, 144B, and 144C, a force is exerted to move toward the reference side. Shortly after the leading edge of the sheet material exits the skew feeding roller pair 144C, the lateral edge of the sheet material becomes the reference side, and the lateral registration is completed.
The sheet material that has undergone the lateral registration stops when the tip position is detected by a photo interrupter (not shown) via the sensor lever 145 further downstream.
[0128]
After matching the next sheet material in the sheet material storage box 108 in sequence, the sheet material conveyance path 146 is advanced again. Next, the transport roller 148 advances the transport path 147, and the path is greatly changed in the upward direction. Further, the paper is discharged from the double-sided device 102 by the conveying roller 149 and is guided again to the main body side.
[0129]
In the sheet material storage box 108, a conveyance path 108A is provided for taking in and conveying the sheet material discharged from the double-sided device 102.
[0130]
The sheet material that has reached the registration roller pair 112 via the conveying roller 111 is then discharged after the toner image is transferred and fixed onto the second surface in the same manner as in the first surface printing described above. It is discharged to the tray 117.
[0131]
FIG. 10 shows in detail a flowchart until the sheet material S passes through the fixing device 114, passes through the decurling roller pair 123 and the conveying roller 127, and is switched back by the decurling roller pair 129.
[0132]
That is, first, it is determined whether or not the conveyance of the sheet material has been started based on the presence or absence of a drive start signal such as a print start signal (step 2). When the start signal is read, a motor (not shown) of the curl removing roller pair 129 is driven. Is started (step 3). This driving direction is the forward rotation direction (CCW), and the motor CCW flag is set.
[0133]
When the leading edge of the sheet material is detected (step 4), the timer starts to operate (step 5). When the trailing edge of the sheet material is detected (step 6), the timer is turned off and a predetermined amount of sheet material is fed. (Step 7). Then, it is determined whether or not the sheet material is a target for curl correction processing (step 8). If the sheet material is not a correction target, the curl correction process ends, and the process proceeds to the setting of the transport destination and transport amount in (step 18). . On the other hand, if the sheet material is to be corrected, it is determined whether the sheet material size is known (step 9). If the sheet material size is not known, the sheet material length is calculated from the timer value (step 10). In step 11, the curl correction length and the number of repetitions set in advance are read, and the curl correction process is started (step 12).
[0134]
First, motor reverse driving is started and the motor CW flag is set (step 13). Next, it is determined whether or not a predetermined amount of back has been achieved in accordance with the curl correction length (step 14). When the predetermined amount of back has occurred, the forward rotation of the motor is started and the motor CCW flag is set (step 15). Next, it is determined whether or not the predetermined amount has been returned (step 16). When the predetermined amount has been returned, it is determined whether or not the curl correction has been completed (step 17). This end determination is made based on, for example, whether or not a predetermined number of repetitions has been reached. If not finished yet, the process returns to (Step 13) and the above procedure is repeated.
[0135]
When the curl correction is completed, the process proceeds to step 18 where the conveyance of the sheet material is started based on the conveyance conditions such as the preset conveyance destination and conveyance amount, and when the predetermined amount is conveyed (step 20), the conveyance is stopped. Then, the motor drive is stopped (step 21).
[0136]
(Effect of Embodiment 1)
Because it is a double-sided device with the above configuration,
(1) Since it is not necessary to lower the fixing temperature control, it is not necessary to sacrifice the fixing property at a low temperature.
(2) Since the sheet material S that has passed through the fixing device 114 reciprocates at the position of the decurling roller pair 129, the curl correcting force can be increased.
(3) The sheet material that has passed through the fixing device 114 is capable of switching the conveyance direction at the position of the decurling roller pair 123 in a specific situation, and reciprocates. That is, when the sheet material S is transported in a direction in which the plowing direction is perpendicular to the traveling direction and the fixing temperature is set high (when the power is turned on), the curl correction effect is automatically obtained. It is possible to up.
(4) Here, the reciprocating region is a region that returns from the rear end of the first surface to the front end side.
[0137]
Further, the rear end of the first surface becomes the front end side in the traveling direction (the front end of the second surface) by performing a switchback operation with the curl removing roller pair 129. Therefore, the ability to correct curl can be improved in a region corresponding to the one-way portion of the reciprocating motion from the tip of the second surface.
[0138]
That is, since the amount of curl at the second surface is reduced, it is possible to eliminate corner breaks and jams in the conveyance due to the curl of the tip. Therefore, it is possible to expand the media specifications that allow double-sided printing.
(5) The sheet material S is exposed when the sheet material S reciprocates in the curl removing roller pair 123.
[0139]
Accordingly, the sheet material heated by the fixing device 114 is cooled by touching the outside air during curl correction. This cooling effect makes it possible to adjust the curl correction force in a further increasing direction.
[0140]
Furthermore, it is possible to prevent the heated sheet material S from increasing the internal temperatures of the double-sided device 102 and the printer main body 103 by radiating heat during conveyance.
(6) Since the decurling roller pair 123 is provided at a position away from the fixing roller 114, the face-up tray 1160 does not interfere with each other when the face-up tray 1160 is used (1160A).
[0141]
Therefore, it is not necessary to pull the sheet material reversing device 121 in the left direction of the drawing to escape, and the sheet material reversing device 121 can be used only by opening the cover 1210 facing the face-up tray 1160, so that the paper handling property is improved.
(7) Since this sequence is applied to the sheet material S of a specific size only when the fixing temperature is high, the time loss associated with the reciprocating motion and the decrease in throughput in continuous feeding are suppressed to the minimum necessary level. Is possible.
(8) When the sheet material S moves backward in the curl removing roller pair 123, the conveyance path is composed of the sheet material conveyance paths 124A and 124B and the inclined portion 125A. You may extend this conveyance path to the upper back surface 1160A of the face-up tray 1160. In this way, the area of the inclined portion 125A can be reduced.
[0142]
Therefore, the cost of the conveyance guide 125 can be reduced.
[0143]
Next, by changing a part of the embodiment applied to the double-sided device 102, the following modified embodiment is possible. Description of common parts is omitted, and only changed parts are described.
[0144]
[Second Embodiment]
When the double-sided device 102 is used, first, the humidity near the sheet material is detected by a humidity sensor (not shown) provided near the sheet material storage box 108. Alternatively, the detected humidity data is stored for several days until now, and the storage condition of the sheet material is inferred.
Based on these conditions, if the switching conditions (sheet material conveyance speed, reverse distance, number of times of switching, etc.) in the curl removing roller pair 123 are set, the curl correction can be performed in consideration of the humidity factor.
[0145]
If a temperature sensor is added, curl correction can be made with the temperature factor added.
[0146]
An example of the curl correction condition is shown in FIG.
[0147]
The curl correction condition table 3 shown in FIG. 11A is the same as the condition of the curl correction condition table 1 described above. The curl correction condition table 4 shown in FIG. 11B is divided into a high temperature / high humidity time, a low temperature / high humidity time, and a low temperature / low humidity time.
[0148]
[Third Embodiment]
FIG. 12 is a diagram showing a third embodiment of the present invention.
[0149]
The position of the swingable guide 1220 that is close to the upstream of the decurling roller pair 123 is switched to the position 1220B by a solenoid (not shown) or the like, so that the sheet material can flow backward to the reverse connection path 120.
[0150]
Then, not only the case of being guided to the dedicated conveyance path 124 but also the case of being guided to the reverse connection path 120 is set at the time of reverse traveling. On the other hand, the reverse path 120 has a smaller curvature than that of the transport path 124 in the shape of the transport path during reverse travel.
Therefore, the curl correction force can be set to be weaker when guided to the reverse connection path 120 than when guided to the dedicated conveyance path 124.
[0151]
Therefore, it is possible to set the curl correction force in a wider range in the direction of increasing the curl correction force. As a result, it is possible to further expand the media specifications that can be used in the duplex device.
[0152]
[Fourth Embodiment]
FIG. 13 is a diagram showing a fourth embodiment of the present invention. This is a case where a part of the third embodiment is further deformed.
[0153]
When the guide 1220 is at the position 1220B, the sheet material S moves backward to the reverse connection path 120.
[0154]
At this time, a guide 1221 whose position can be switched is provided in the reverse connection path 120. When the guide position is 1221B, a branch conveyance path 1225 is provided in which the sheet material that moves backward is guided downward. The direction of curvature of the branch conveyance path 1225 is set on the opposite side to that of the conveyance path 124. Reciprocating along the branch conveyance path 1225 increases the downward curl amount after fixing.
[0155]
Therefore, it is effective in the sense that the curl correction effect in the decurling roller pair 123 is too strong and is actually weakened.
[0156]
For example, when the sheet material is thick or the basis weight is heavy, the curl correction effect by the decurling roller pair 123 is large. In other words, even when in the lower curl state after passing through the fixing device, after passing through the decurling roller pair 123, the curl direction is reversed to be in the upper curl state. If the curl amount exceeds a certain level, corner breaks and jams are generated in the apparatus, as in the case of a hygroscopic sheet material.
[0157]
In such a case, the lower curl state can be strengthened by setting so as to be guided to the branch conveyance path 1225 during reverse travel.
[0158]
As a result, before entering the decurling roller 123, it becomes the same as the case where the lower curling amount is increased, so that the curling amount after passing through the decurling roller pair 123 can be made appropriate.
[0159]
Since it is difficult for the apparatus to recognize that the sheet material S is thick, it is referred to as a thick paper mode, and it is desirable that the user sets it from an operation unit or the like in the printer main body 100.
[0160]
FIG. 14 is a diagram illustrating a communication relationship between the duplex device 102 and the printer main body 100 in the present embodiment. Setting of the curl correction condition in the option control device 102A is performed from the main body control device 100A through the in-machine communication line S1.
[0161]
FIG. 15 is a diagram illustrating a display method on the operation unit 100B1. In the figure, selection / setting is performed while viewing the menu shown on the display unit 100B1 of the display / operation unit 100B.
[0162]
FIG. 16 is a flowchart showing an outline of in-flight communication.
[0163]
In the figure, the double-sided device 102 that has received a communication interruption from the laser beam printer 100 (step 2) checks whether there is a communication problem (step 3), and if it is determined that there is an error (step 4), Error processing is performed (step 9).
[0164]
If it is determined to be normal (step 4), the communication content is decoded (step 5), and data fetch processing is performed according to each code (steps 6, 7, 8).
[0165]
In this embodiment, the curl correction condition is set from the operation unit 100 of the laser beam printer 100. However, the curl correction condition can also be set by a changeover switch (not shown) provided in the double-sided device 102.
[0166]
FIG. 17 shows a flowchart when the changeover switch is used.
[0167]
In the figure, the curl control unit detects the curl correction condition switch state using the sheet material entry waiting time (step 2) (step 7). The curl correction condition is selected according to the state of the switch (step 8) and (step 9).
[0168]
When a sheet material signal is received (step 2), paper pull-in processing is performed (step 3), curl correction conditions selected by the switch are extracted (step 4), and curl correction processing is performed (step 5).
[0169]
An example of the curl correction condition is shown in FIG.
[0170]
The curl correction condition table example 5 in FIG. 18A is the same as the curl correction condition table example 1 described above.
[0171]
In the curl correction condition table 6 shown in FIG. 18B, conditions are set so that correction processing is performed when the switch is 0N and correction processing is not performed when the switch is OFF.
[0172]
Since the present embodiment has the above configuration,
(1) The curl correction force can be adjusted not only in the direction of further increasing but also in the direction of decreasing.
(2) Changing the curl correction conditions with the operation unit or changeover switch is effective for optimizing the curl correction conditions for special sheet materials such as thick sheet materials that are difficult for the device to automatically recognize. It is. Therefore, it is possible to further expand the media specifications capable of duplex printing.
[0173]
[Fifth Embodiment]
FIG. 19 is a diagram showing a fifth embodiment of the present invention. In the first to fourth embodiments, the guide 125, which is a part of the dedicated transport path during reverse travel, is improved.
[0174]
In the present embodiment, the guide 1250 that is a part of the dedicated conveyance path has two wing portions that form an opening angle in the traveling direction, and is integrally molded. The opening angle is set so as to stably convey from a small size (for example, A5Y) to a large size (for example, A3T). Further, the wing portion has end faces 1250A and 1250B which become a conveying surface when the sheet material moves backward by the curl removing roller pair 123.
[0175]
Further, the bottom surface has four claw portions 1250C, 1250D, 1250E, and 1250F (so-called patch-on claw) protruding downward, and further, the square windows 1211C, 1211D, and 1211E of the cover 1211 at positions facing the claw portions. , 1211F. Then, by removing the claw portion, it is possible to detach it.
[0176]
FIG. 20 is a diagram comparing the packing forms in the case where the present embodiment having the above configuration is applied and in the case where the embodiment is not applied. When packing the double-sided device, if the guide 1250 is removed and moved to an empty space, the packing volume can be reduced (h2 <h1).
[0177]
Therefore, logistics efficiency is improved.
[Sixth Embodiment]
FIG. 21 is a diagram illustrating the sixth embodiment. The guide 1250 according to the fifth embodiment is further improved.
[0178]
The guide 1251 in this embodiment includes two wing parts 1251 and 1252 that can swing around a shaft part 1251A and a shaft part 1252A.
[0179]
Further, square windows 1251B and 1252B are opened in the wing portions 1251 and 1252, respectively. The corner windows 1251B and 1252B are pivotally supported with swingable pieces 1253 and 1254 that can swing according to their sizes.
[0180]
The swinging pieces 1253 and 1254 can swing to the illustrated position while being urged by a torsion spring or the like (not shown) around the shaft portions 1253A and 1254A. Then, the one end surfaces 1253B and 1254B of the swing piece come into contact with the surface of the cover 1212 so that the wing portions 1251 and 1252 have a specified opening angle.
[0181]
When storing, if a force is applied from above the wing parts 1251 and 1252, the swing piece 1253 and the swing piece 1254 rotate against the urging force and are stored in the square windows 1251B and 1252B. At the same time, the wing part also rotates and is stored near the surface of the cover 1212.
[0182]
Since it is the said structure, it is possible to improve physical distribution efficiency, without removing a wing part at the time of packing.
[Seventh Embodiment]
FIG. 22 is a seventh embodiment to which the present invention is applied, and is a cross-sectional view when applied to a laser beam printer as an example of an image recording apparatus.
[0183]
In the laser beam printer 103, a video controller board (image signal generating means) 104 generates an image signal based on information transmitted from an external information device such as a personal computer or a word processor. Here, various electronic components installed on the video controller board 104 are not shown.
[0184]
The laser beam L ′ corresponding to the image signal created by the video controller board 104 is irradiated onto the photosensitive drum 106A in which the laser scanner 105 rotates clockwise, and electrostatic latent images are sequentially formed on the photosensitive drum 106A. Form.
[0185]
The electrostatic latent image formed on the photosensitive drum 106 </ b> A is successively visualized by toner supplied from a developing device (not shown) in the process unit 106 and conveyed to a transfer portion between the transfer roller 107. .
[0186]
On the other hand, the sheet material S ′ loaded and stored in the sheet feeding cassette 108 is sequentially fed out one by one from the uppermost sheet material to the sheet feeding path 110 by the half-moon shaped sheet feeding roller 109 that rotates once counterclockwise. Then, the sheet is conveyed to the registration roller pair 112 whose rotation is stopped by the conveyance roller pair 111.
[0187]
The sheet material S ′ that has reached the registration roller pair 112 is continuously conveyed until a predetermined loop is formed after the leading end of the sheet material S ′ has hit the nip of the registration roller pair 112 to correct the skew state.
[0188]
The sheet material S ′ that has been corrected for the skew state is conveyed to the transfer unit by the registration roller pair 112 that starts rotating at the timing of aligning the position with the toner image on the photosensitive drum 106A. The toner image on the photosensitive drum 106A is transferred onto the sheet material surface by 107.
[0189]
After the transfer of the toner image, the sheet material S ′ is conveyed to the fixing device 14 through the conveyance guide 113, and the transferred toner image is fixed on the sheet material surface.
[0190]
In the fixing device 14, an endless heat resistant film 310 is externally fitted to a support member 312 including a heater 311. The heat resistant film 310 is driven while being in pressure contact with the pressure roller 314 facing the sheet, and conveys the sheet material.
[0191]
At that time, heat is applied from the heater 311 to the toner on the sheet material through the heat resistant film 310. The heat generation temperature is determined by a CPU (not shown) based on a temperature measuring element 313 such as a thermistor. The current flowing from the heating element (not shown) to the heating element is controlled by a triac (not shown) so as to maintain a predetermined temperature.
After completion of the toner image fixing process, the sheet material S ′ cuts the fixing paper discharge sensor 315A, passes through the transport path 301, and is transported to the roller pairs 302 and 304.
[0192]
The curl correction path 303 between the roller pairs 302 to 304 has a shape with a certain curvature. In this curl correction pass, the rotation direction of the roller pairs 302 and 304 is changed over several times by repeating the reverse rotation several times at a predetermined time based on the information of the fixing paper discharge sensor, and the sheet is changed. The material is repeatedly conveyed.
[0193]
In this case, the number of repetitions and the conveyance time can be changed according to the sheet material size and the amount of heat applied to the sheet material.
[0194]
The amount of heat applied to the sheet material is obtained based on information from a temperature measuring element 313 such as a thermistor disposed in the above-described fixing device. By this operation, when the fixing temperature control is changed, the generated curl state is changed, and appropriate curl correction corresponding to that is performed.
[0195]
After the curl correction is completed, the paper is discharged from the paper discharge roller 306 to the paper discharge tray 117 in the conveying direction indicated by the arrow A face down with the print side facing down and stacked. (Loading paper 307)
(effect)
The present embodiment has the above-described configuration and operation. When the amount of heat applied to the sheet material differs depending on the size, thickness, sheet material, and the like of the sheet material, the curled state also changes. The curl correction corresponding to each different sheet can be performed in this different state, and there is an effect of improving the transportability and stackability at the time of paper discharge. [Eighth Embodiment]
FIG. 23 is an eighth embodiment to which the present invention is applied, and is a cross-sectional view when applied to a laser beam printer as an example of an image recording apparatus, as in the seventh embodiment. Since the process until the sheet material reaches the fixing device in this example is the same as that in the fourth embodiment, the description thereof is omitted.
[0196]
In the fixing device 330 according to the eighth embodiment, the roller 332 includes a heater 333 at the center, and rotates while applying pressure to the sheet material by the pressure roller 331 to apply heat to the toner on the sheet material. .
[0197]
The sheet material S ′ that has passed through the fixing device cuts off the fixing paper discharge sensor 315, and is sent from the conveyance path 301 to the branch conveyance path 320 by the conveyance roller 302.
[0198]
Here, the direction is directed toward the curl correction roller 322 by the deflector 324A.
[0199]
The curl correction roller 322 determines the timing at which the rear portion of the sheet material passes through the deflector 324A based on information from the fixing paper discharge sensor 315.
[0200]
At this timing, the deflector is rotated from 324A to 325B. At the same time, the curl correction roller 322 rotates in the reverse direction and the sheet material is conveyed to the curl correction path 325.
[0201]
The curl correction roller pair 322 corrects curl by causing the sheet material to follow the curl correction roller within a certain angle by two opposing rollers. The nip shape of the curl correction roller pair 322 is a direction in which an upward curl is formed in a concave shape on the upper side, and is a direction that promotes the curl direction of the sheet material on which the downward curl is attached in the fixing device 330. Due to the curvature of 320, it is considered that the curl is in the reverse direction, that is, in front of the curl correction roller pair 322, and the downward curl is corrected. However, depending on the shape of the conveyance path, the curl may be in an upward curl state, or the curl direction in the fixing device may be an upward curl depending on the conditions. In short, the shape of the nip portion of the curl correction roller pair 322 is: The curl direction of the front sheet material is set to a direction for correcting.
[0202]
In this curl correction path 325, the rotation direction of the curl correction roller pair 322 is repeatedly reversed several times at a predetermined time, whereby the conveyance direction is switched and the sheet material is repeatedly conveyed.
[0203]
In this case, the number of repetitions and the conveyance time can be changed according to the sheet material size, the temperature around the sheet material, and the humidity.
[0204]
The temperature and humidity around the sheet material to be fed are detected by a temperature / humidity sensor installed in the vicinity of the sheet feeding cassette and the sheet feeding tray. By this repeated operation, when the sheet material to be fed changes depending on the temperature and humidity of the surrounding environment, the generated curl state changes, and appropriate curl correction corresponding to that is performed.
[0205]
After the curl correction is completed, when the laser beam printer 327 is selected in the single-sided image forming mode, the curl correction roller pair 322 conveys the sheet material in the direction of arrow A and the first discharge roller pair 306 causes the first discharge. The paper is discharged from the outlet to the paper discharge tray 117.
[0206]
When the laser beam printer 327 is selected in the double-sided image forming mode, the deflector is switched from the position 324B to the position 324A, and the laser beam printer 327 is discharged from the second discharge port 333 to the outside of the main body 327. The second outlet 333 is an outlet to the optional unit that is detachably connected to a main body 327 such as a duplex unit that conveys the sheet material for printing the back surface and a stacker for separating and stacking the sheet material. It is.
[0207]
The sheet material discharged from the second discharge port 333 is conveyed from the entrance path 334 of the duplex unit to the duplex unit 335, and the skew feeding roller unit having a sheet material position correcting mechanism by the conveyance roller pair 23 and 27. It is conveyed to 28.
[0208]
The oblique feeding roller unit 128 includes a reference plate having a surface parallel to the transport direction and a pair of oblique feeding rollers 30 and 31 that are in pressure contact with a roller having an arbitrary inclination.
It is a mechanism that corrects the position of the sheet material by conveying it by the pair of skew feeding rollers 130 and 131 and aligning the sheet material with a reference plate.
After the position correction is completed, the sheet material is conveyed through the refeed path 33 by the conveyance roller 32 and is conveyed again to the registration roller pair 112 whose rotation is stopped.
[0209]
The cassette 108 has a passage 108 </ b> A that forms part of the refeed path 33. After the sheet material that has reached the registration roller pair 112 is transferred to the second surface and fixed in the same manner as in the case of the first surface described above, the sheet material is discharged onto the discharge tray 117. Is done.
[0210]
(effect)
The present embodiment has the above configuration and operation and has the following effects.
(1) The ambient temperature and humidity around the installation of this apparatus vary depending on the region, season, and time zone, and the sheet material generates different curls when left in those environments. By providing the temperature / humidity sensor and the curl correction mechanism, the curl correction can be performed at any time according to the environmental temperature and humidity on the spot.
(2) By folding the curl removal path and making it detachable, it can be reduced in size by being folded or removed in an environment that does not require curl correction, and the use space can be reduced.
(3) By performing curl correction on the printer apparatus main body side and enabling discharge from the second discharge port, it is possible to improve transportability in the external connection apparatus.
(4) When the double-sided unit is installed as the external connection device, the second discharge port is discharged in the transport direction opposite to the discharge tray side which is the first discharge port. Can be sent to the double-sided unit in a state of being switched back, so there is no need to provide a switchback path in the double-sided unit, and the double-sided unit can be downsized.
(5) By providing a curl correction path between the first discharge port and the second discharge port, it is possible to correct the curl regardless of whether the discharge is performed by one curl correction mechanism.
[0211]
[Ninth Embodiment]
FIG. 24 shows a ninth embodiment to which the present invention is applied, and is a cross-sectional view when applied to a laser beam printer as an example of an image forming apparatus, similarly to the seventh and eighth embodiments. In the present embodiment, the process until the sheet material reaches the fixing paper discharge sensor is the same as that in the seventh embodiment, and a description thereof will be omitted.
[0212]
After passing through the fixing paper discharge sensor 315A, the curl amount is detected by the curl amount detection sensor 345 in the conveyance path 336, and conveyed to the first curl correction conveyance path 331 by the conveyance roller pair 302. The deflector is moved to the position of 330A based on the information of the fixing paper discharge sensor 315A, the sheet material is conveyed to the curl correction roller pair 334 through the conveyance path 337, and reaches the second curl correction path 342.
[0213]
The curl correction roller pair 334 corrects curl by causing the sheet material to follow the curl correction roller pair within a certain angle by two opposing rollers.
[0214]
When the trailing edge of the sheet material passes through the switchback sensor 336A, the curl correction roller pair 334 and the conveying roller 302 or 339 rotate in the reverse direction and start conveying in the opposite direction.
[0215]
At this time, either the first curl correction path 331 or the third curl correction path 338 is selected based on the information of the curl amount detection sensor described above. As a result, the deflector is moved to the position of 330A or 330 and guided to either.
[0216]
Before the sheet material passes through the curl correction roller pair 334, the curl correction roller pair 334, the conveyance roller pair 302, or 339 rotates again and is conveyed to the second curl correction path 342 side.
[0217]
The curl correction is performed by repeating this repeated operation several times. However, the number of repetitions and the selection of the curl correction path can be changed at any time in order to perform appropriate curl correction according to the information of the curl amount detection sensor.
Further, the first curl correction path 331 and the second curl correction path 338 have different curvatures, and the amount of curl correction can be changed by switching the paths.
[0218]
After completion of curl correction, the sheet material passes through the curl correction roller 334 and the conveyance path 337, and is conveyed to the first curl correction path 331 or the third curl correction path 338, and the deflector is positioned at 330B or 330A. The paper is conveyed to a paper discharge path 341 and is discharged from a paper discharge port by a paper discharge roller 306.
[0219]
The sheet material is sorted and stacked by a detachable multi-stage stacking tray 343 arranged at the sheet discharge port.
(effect)
The present embodiment has the above configuration and operation and has the following effects.
(1) The curl amount of the sheet material that has passed through the fixing device is detected as needed, and the curl correction can be performed according to the size.
(2) By providing a curl correction roller and two types of curl correction paths having different curvatures as the curl correction mechanism, fine adjustment of the amount of curl correction is possible over a wide range.
(3) By disposing a detachable multi-stage stacking tray unit at the paper discharge port after the curl correction, stackability can be improved both when the multi-stage stacking tray is used and when the main body stacking tray is used.
[Tenth embodiment]
FIG. 25 shows a tenth embodiment to which the present invention is applied, and is a cross-sectional view when applied to a laser beam printer as an example of an image recording apparatus, as in the seventh, eighth, and ninth embodiments. In the present embodiment, the process until the sheet material reaches the fixing / discharging sensor 315A is the same as that in the seventh embodiment, and a description thereof will be omitted.
[0220]
After the fixing sheet discharge sensor 315A is cut, the sheet is conveyed to the conveyance path 357 by the conveyance roller 336.
[0221]
Here, when the laser beam printer 380 is face-down with the printing surface facing down in the single-sided image forming mode and the main body discharge tray is selected, the deflector 358A guides the discharge path 360 to the discharge path 360. The paper is discharged to the discharge tray 117 by the paper roller 306.
[0222]
In cases other than the above, the deflector is positioned at 358C and discharged from the second discharge port 359.
[0223]
As with the seventh embodiment, the double-sided unit 374 can perform an image forming apparatus only on one side only with the configuration of the main body device 380 itself. However, by attaching a detachable double-sided unit, an image is formed on both sides of the sheet material. A unit for enabling the forming apparatus.
[0224]
The multi-stage stacking tray unit 350 is a unit that can be attached to and detached from the main body device 380 and the double-sided unit 374 and can stack sheets separately.
[0225]
The sheet material discharged from the second discharge port is drawn into the double-sided unit 374 from the first roller pair 379 of the double-sided unit 374, cuts the sensor 363, and is conveyed to the curl correcting roller pair 364.
[0226]
When the trailing edge of the sheet material passes through the sensor 363, the curl correction roller pair 364 rotates reversely, the deflector 361A is moved to the position of 361B, and is sent to the conveyance path 375 in the multi-stage stacking tray unit. After the sheet material is conveyed by the curl correction roller for a certain period of time, the curl correction roller rotates in the reverse direction again to switch the conveyance direction.
The conveyance time and the number of repetitions of this repetitive conveyance are changed at any time according to the size of the sheet material and the temperature of the sheet material at the time of heating and fixing detected by a temperature detecting element such as a thermistor in the fixing device.
[0227]
The nip shape of the curl correction roller pair 364 is a direction in which a downward curl is formed so as to be concave on the lower side, and is a direction that promotes the curl direction of the sheet material on which the downward curl is attached in the fixing device 14. Depending on the curvature of the path 357, it is considered that the curl is reverse, that is, in front of the curl correction roller pair 364, and this upward curl is corrected. However, depending on the shape of the transport path 357, the curl may be in a downward curl state, or the curl direction in the fixing device 14 may be an upward curl depending on the conditions. In short, the shape of the nip portion of the curl correction roller pair 364 is considered. Is set in a direction to correct the curl direction of the sheet material in front of it.
[0228]
Here, when the face-up discharge with the print side up is selected for the main body discharge tray 117 as the discharge after the single-sided image formation by the laser printer 380, it is drawn into the duplex unit 374 side by the sheet material curl correction roller 364, After that, when the end portion passes through the sensor 363, the curl correction roller pair 364 rotates again, the deflector 361B is moved to 361A, and the 358C is moved to 358B, and is conveyed again into the main body through the conveyance roller pair 3610 and discharged. The paper is discharged from the roller 306 to the discharge tray 117.
[0229]
In addition, when a multi-stage stack tray is selected as the discharge and stacking method after the single-sided image formation by the printer 380, after curl correction is completed, the paper passes through the conveyance path 372 and is discharged to the multi-stage tray 351 by the discharge roller pair 373.
At that time, the multi-stage stacking tray 351 is moved up and down, so that the discharge destination tray can be changed and sorting stacking is possible.
[0230]
When the double-sided image forming mode is selected by the laser printer 380, the sheet material is conveyed to the sensor 366 side after the curl correction is completed, and the trailing edge of the sheet material passes through the sensor 366 by the reversing roller pair 368 and is deflected. It is sent to the switchback path 370 until it passes through 367A.
[0231]
By obtaining the timing at which the rear end of the sheet material passes through the deflector 367A by the sensor 366, the reverse roller pair 368 is reversely rotated, and at the same time, the deflector is switched to 367B, and the sheet material is sent to the conveyance path 25.
Thereafter, the sheet material is conveyed to the oblique feeding roller unit 28 by the conveying roller pair 26, 27, and the position is corrected by the oblique feeding roller unit 28 in the same manner as in the eighth embodiment. It is sent again to the registration roller pair 112 whose rotation is stopped.
[0232]
After the sheet material S ′ that has reached the registration roller pair 112 is transferred to the second surface and fixed in the same manner as in the case of the first surface, the selected discharge port is used. Are discharged and loaded in the selected discharge direction.
(effect)
The present embodiment has the above configuration and operation, and has the following effects.
(1) When the amount of heat applied to the sheet material varies depending on the size, thickness, sheet material, and the like of the sheet material, the curled state also changes. The curl correction corresponding to each different sheet can be performed in this different state, and there is an effect of improving the transportability and stackability at the time of paper discharge.
(2) By providing the double-sided unit that can be attached to and detached from the laser printer main body and the multi-stage stacking tray unit with a repetitive conveyance path during curl correction, the configuration of the main body device alone can be simplified and downsized. Moreover, two types of discharge and stacking of face-down and face-up are possible with one discharge tray in the main body.
[0233]
【The invention's effect】
  CheapWith a reasonable configuration, it is possible to provide a curl correcting means that can adjust the curl correcting force in a direction that dramatically increases.
[Brief description of the drawings]
FIG. 1 is a first diagram illustrating a basic configuration of the present invention.
FIG. 2 is a diagram showing a flowchart of control in the basic configuration of FIG. 1;
FIG. 3 is a diagram showing a timing chart for control in the basic configuration of FIG. 1;
FIG. 4 is a second diagram illustrating the basic configuration of the present invention.
FIG. 5 is a diagram showing a flowchart of control in the basic configuration of FIG. 2;
6 is a timing chart for control in the basic configuration of FIG. 2;
FIG. 7 is a diagram showing a first embodiment of the present invention.
FIG. 8 is a diagram showing a communication relationship in the first embodiment of the present invention.
FIG. 9 is a diagram illustrating an example of a curl correction condition according to the first embodiment of the present invention.
FIG. 10 is a diagram showing a flowchart of control in a curl correction unit according to the first embodiment of the present invention.
FIG. 11 is a diagram illustrating an example of curl correction conditions according to the second embodiment of the present invention.
FIG. 12 is a diagram showing a third embodiment of the present invention.
FIG. 13 is a diagram showing a fourth embodiment of the present invention.
FIG. 14 is a diagram showing a communication relationship in the fourth embodiment of the present invention.
FIG. 15 is a diagram illustrating a display method of an operation unit according to the fourth embodiment of the present invention.
FIG. 16 is a flowchart illustrating control according to the fourth embodiment of the present invention.
FIG. 17 is a diagram showing a flowchart when a changeover switch is used in the fourth embodiment of the present invention.
FIG. 18 is a diagram showing an example of curl correction conditions according to the fourth embodiment of the present invention.
FIG. 19 is a diagram showing a fifth embodiment of the present invention.
FIG. 20 is a view showing a packing form according to the fifth embodiment of the present invention.
FIG. 21 is a diagram showing a sixth embodiment of the present invention.
FIG. 22 is a diagram showing a seventh embodiment of the present invention.
FIG. 23 is a diagram showing an eighth embodiment of the present invention.
FIG. 24 is a diagram showing a ninth embodiment of the present invention.
FIG. 25 is a diagram showing a tenth embodiment of the present invention.
[Explanation of symbols]
1000 Curling roller pair
3000 levers
2000 Driving source
1011 Conveying roller pair
3001 Detection means
2001 Drive source
123 Curling roller pair
124 Conveyance path
125 Transport guide
129 Curling roller pair
131 Transport path
1220 Guide
120 Reverse connection path
1221 Guide
1225 Branch transfer path
1250 guide
1251 Guide
303 Curl correction path
315 Fixing paper discharge sensor
322 Curl straightening roller pair
324 Deflector
325 Curl Correction Pass
331 First curl correction pass
334 Curl correction roller pair
338 Third curl correction pass
342 Second curl correction pass
343 Multi-stage tray
358 Deflector
361 Deflector
368 sensor
351 Multi-stage tray

Claims (16)

Curl correction means for correcting the curled sheet material;
A driving means capable of switching the conveying direction of the sheet material at a predetermined switching position of the sheet material conveying path including the curl correcting means and performing an operation of passing the sheet material through the curl correcting means a plurality of times;
According to the curl characteristic of the sheet material, a switching condition at the time of the sheet material conveyance direction switching operation can be set. By driving the driving means based on the switching condition, the curl correction force on the sheet material is increased. And means for adjusting ,
(I) As the switching condition, it is possible to set the number of times of switching during the operation of passing the sheet material through the curl correcting means a plurality of times, and the means for adjusting the curl correcting force is the sheet material at the set switching frequency Or (ii) as the switching condition, a switching distance that is a distance for conveying the sheet material after switching the conveyance direction of the sheet material can be set. The means for adjusting the curl correction force drives the driving means so as to switch the conveyance direction of the sheet material at a set switching distance.
A sheet material transport mechanism.   The sheet material conveyance mechanism according to claim 1, further comprising a detection unit configured to detect a switching position in order to switch the conveyance direction of the sheet material.   The sheet material conveying mechanism according to claim 1, wherein the sheet material conveying mechanism has a dedicated conveying path branched from the sheet material conveying path as a conveying path at the time of switching the sheet material conveying direction. The sheet material conveyance mechanism according to claim 3, wherein the dedicated conveyance path is detachably provided. The sheet material transport mechanism according to claim 3, wherein the dedicated transport path is provided so as to be retractable. The sheet material transport mechanism according to claim 3, wherein the dedicated transport path is a part of another adjacent apparatus main body. In the dedicated transport paths, a sheet material conveying mechanism of claim 3, the sheet material is characterized in that it is a structure that is exposed.   The sheet material conveyance mechanism according to any one of claims 1 to 7, wherein after the sheet material conveyance direction switching operation is completed, the sheet material is further guided to a reverse conveyance unit on a downstream side in the conveyance direction. After completion of conveying direction switching operation of the sheet material, the sheet material conveying mechanism according to any one of claims 1 to 8, characterized in that leads to the sorter. The sheet material conveyance according to any one of claims 1 to 9 , wherein the curl correcting means is configured by a roller pair including a nip portion having a curvature shape opposite to a curled state of the sheet material. mechanism. The sheet material conveying mechanism according to any one of claims 1 to 10 , wherein the curl correcting means is configured by a conveying path having a curvature shape opposite to a curled state of the sheet material. On the upstream side in the sheet material conveying direction of the curl correcting means, a heating means, a heat resistant film for transferring heat from the heating means contacting one surface to the other surface, the heat resistant film and the heat resistant film. Pressurizing means for forming a nip portion by heating contact with the adhesive film, and heating and fixing the image on the recording material by holding and transporting the recording material carrying the unfixed image in the nip portion. the sheet material conveying mechanism as claimed in any one of claims 1 to 11, characterized in that it comprises a fixing device. Wherein the sheet material conveying direction upstream side of the curl correcting section, the sheet material conveying mechanism according to any one of claims 1 to 12, characterized in that an image forming process. It said drive means, the sheet material conveying mechanism according to any one of claims 1 to 13, characterized in that a pulse motor. An image, comprising: an image recording unit that records an image on a sheet material; and a sheet material conveyance path including the sheet material conveyance mechanism according to any one of claims 1 to 14. Recording device. A fixing unit for fixing an unfixed image recorded by the image recording unit, the sheet material conveying according to any one of claims 1 to 14 to the sheet material conveying path in the conveying direction downstream side of the fixing portion The image recording apparatus according to claim 15 , wherein a mechanism is provided.

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