JP4893497B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a recording material.

  An electrophotographic image forming apparatus generally includes a heat fixing device that fixes a toner image on a recording material by heating and pressing.

  In heat fixing, there is a problem called uneven wax and a problem of curling of the recording material, and countermeasures against these are taken.

  Unevenness of wax is a phenomenon in which the toner image immediately after fixing comes into contact with parts inside the image forming apparatus and the surface of the image can become uneven. Before the wax contained in the toner cools and solidifies, the transport roller, guide, belt, etc. By contacting the part, the image has unevenness and uneven luster, and the image quality deteriorates. When the amount of toner that forms an image is large, such as a color image, uneven wax is particularly likely to occur.

  Although moisture evaporates from the recording material that has been heated and heated in the fixing device, if the evaporation rate differs between the front and back surfaces of the recording material, there is a difference in shrinkage after fixing between the front and back sides. In some cases, the recording material may be curved, which is a typical example of curling.

  In addition to these fixing-related problems, when the recording material is ejected, the recording material does not advance straight, but immediately after it exits the ejection port of the image forming apparatus, the recording material bends downward, and the ejection tray There is a problem that it may not be loaded in order.

  Conventionally, measures have been taken individually for these problems.

  That is, with respect to the unevenness of the wax, a countermeasure has been taken to reduce the area in contact with the recording material by using a conveyance roller having an uneven surface.

  Various measures have been taken against curling, but typically, as in Patent Document 1, the curled recording material is passed through a curved conveyance path opposite to the curling of the recording material. , Curled.

For the deflection of the recording material during paper discharge, a measure for imparting straightness to the recording material by corrugation that bends the recording material in the conveyance width direction as in Patent Document 2 has been taken.
JP-A-2-88272 JP-A-5-43110

  As described above, conventionally, countermeasures have been individually taken for each type of problem with respect to problems that occur in the conveyance of the heat-fixed recording material. And there existed a problem that it became large sized and cost became high.

  In particular, the countermeasure against wax unevenness increases the cost because a special roller having irregularities formed on the surface is used as the transport roller.

  Even when the contact area is reduced by the unevenness, the wax unevenness is not completely eliminated because there is a contact portion.

  In addition, when a measure for eliminating the bending by corrugation is taken, a new problem arises that a stripe parallel to the transport direction can be formed on the recording material.

  The present invention provides an image forming apparatus that solves the above-described problems in the related art relating to the conveyance of the recording material after the fixing process, and that is small and solves the problem in the conveyance of the recording material after the fixing process at a low cost. Objective.

The object is achieved by the following invention.
1.
In an image forming apparatus including an image forming unit that forms an image on a recording material, a fixing device that fixes an image on the recording material, and a conveyance unit that conveys the recording material discharged from the fixing device.
The transport unit includes a transport unit that supports and transports the recording material, and a fan that is provided to face the transport unit and generates an airflow toward the transport unit, and is arranged in parallel in the transport width direction. Having a transport unit ,
The conveyance surface of the recording material is changed by forming a conveyance surface curved in the conveyance width direction by tilting a part of the conveyance unit arranged at the end in the conveyance width direction. Image forming apparatus.
2 .
The transport unit has a plurality of rollers arranged side by side in the transport direction and a belt stretched around the rollers, and the curved transport surface is formed by tilting a part of the shaft of the rollers. 2. The image forming apparatus as described in 1 above.
3 .
3. The image forming apparatus according to claim 1 or 2 , wherein when the transport surface is changed, the transport surface closer to the fixing device is maintained in a flat plate shape.
4 .
Before Ki搬 transmission unit rotates about an axis parallel to the conveying width direction, the image forming apparatus according to 1, wherein the conveying path for conveying is switched to the recording material.
5 .
Either a curl detection sensor that detects the curl of the recording material, a paper thickness detection sensor that detects the thickness of the recording material, an environment detection sensor that detects at least one of temperature and humidity, and a setting unit that sets the type of the recording material Having at least one and control means;
The control means is arranged at the end in the transport width direction based on information from at least one of a curl detection sensor of the recording material, the paper thickness detection sensor, the environment detection sensor, and a setting unit. 2. The image forming apparatus according to 1 , wherein a part of the transport unit is inclined to form the transport surface curved in the transport width direction, thereby changing the transport surface.

  Since the transport unit for supporting and transporting the recording material and the fan for generating the airflow toward the transport unit constitute a transport unit, and the transport surface of the recording material is changed by moving at least a part of the fan and the transport unit together. In addition, curl correction and corrugation for curving and conveying the recording material, and switching of the conveyance path can be performed by moving the conveyance unit, and various processes to be performed on the recording material being conveyed can be performed by one conveyance unit. As a result, the entire apparatus is reduced in size and the cost is reduced.

  Further, since the processing for the recording material is performed without contacting the image carrying surface of the recording material, it is possible to avoid degradation of the image quality such as wax unevenness.

  Hereinafter, the present invention will be described using embodiments, but the present invention is not limited to the embodiments.

  FIG. 1 shows a color image forming apparatus according to an embodiment of the present invention.

  The illustrated color image forming apparatus includes an automatic document feeder 30, an image reading unit 40, an image forming unit 50, and an operation unit 60 that feed documents one by one to a reading position, and forms a color image on a recording material P. A color image forming apparatus capable of performing the above.

  The image reading unit 40 reads the document d conveyed by the automatic document conveying unit 30 or the document placed on the document table 42 with the reading element 41 and generates image data.

  The image forming unit 50 includes a plurality of process units 10Y, 10M, 10C, and 10K, an intermediate transfer member 9, a fixing device 7, a plurality of recording material storage units 8, and the like.

  A process unit 10 </ b> Y that forms a yellow (Y) image includes a photoreceptor 1, a charging device 2, an exposure device 3, a developing device 4, a primary transfer device 5, and a cleaning device 6 disposed around the photoreceptor 1. Similarly, the process unit 10M that forms a magenta (M) color image, the process unit 10C that forms a cyan (C) color image, and the process unit 10K that forms a black (Bk) color image are also the photoreceptor 1 and the charging device. 3, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6.

  In the figure, only the process unit 10Y is indicated by reference numerals for components constituting the unit, and the reference numerals are omitted for the other process units.

  The intermediate transfer member 9 is wound around a plurality of rollers and is rotatably supported. The fixing device 7 heats and presses the toner on the recording material P by the heating roller 71 and the pressure roller 72 and fixes the toner.

  The images of the respective colors formed by the process units 10Y, 10M, 10C, and 10K are sequentially transferred by the primary transfer device 5 onto the rotating intermediate transfer member 9, and are superimposed on the intermediate transfer member 9 to form a color image. It is formed.

  The recording material P stored in the recording material storage unit 8 composed of a paper feed tray is separated into one sheet by the paper feed roller 21 and fed, and passes through the transport rollers 22 and 23 and is in a stopped state. Paper is fed to Therefore, once stopped, the registration roller 24 starts rotating at the timing when the positional relationship between the leading edge and the toner image on the intermediate transfer body 9 exactly matches, and is fed to the secondary transfer device 5A. A color image is transferred from the transfer body 9 onto the recording material P (secondary transfer). The recording material P to which the color image has been transferred is heated and pressurized in the fixing device 7 so that the color toner image on the recording material P is fixed. Thereafter, the paper is discharged out of the apparatus by the transport unit 100.

  On the other hand, after transferring the color image to the recording material P by the secondary transfer means 5A, the residual toner is removed by the intermediate transfer body cleaning device 6A from the intermediate transfer body 9 which has separated the curvature of the recording material P.

  In the double-sided image formation, a re-feeding unit 120 re-feeds the recording material P having an image formed on the surface thereof to the image forming unit 50, and 121 reverses the recording material P and sends it to the re-feeding unit 120. It is a reversal conveyance part.

  2 is a front cross-sectional view of the fixing device 7 and the transport unit 100, FIG. 3 is a plan cross-sectional view of the fixing device 7 and the transport unit 100, FIG. 4 is a side view of the transport unit 100 as viewed from the paper discharge port side, and FIG. FIG. 3 is a perspective view of a part of a conveyance unit 100 and a fixing device 7.

  The conveyance unit 100 disposed downstream of the fixing device 7 includes a conveyance unit including a fan and a belt unit as a conveyance unit.

  As shown in FIG. 4, the transport unit 100 has three transport units arranged in parallel in the transport width direction of the recording material. Each transport unit includes a fan 101A and a belt unit 102A, a fan 101B and a belt unit 102B, respectively. 101C and a belt unit 102C.

  101A and 1O2A, 101B and 102B, and 101C and 102C are arranged one above the other with the fan on the top and the belt unit on the bottom, respectively.

  Each of the belt units 102A, 102B, and 102C includes two rollers that are arranged back and forth in the transport direction and a belt that is stretched around the rollers.

  Reference numeral 73 denotes a fan provided in the fixing device 7, and heats the recording material P by blowing air from above to the recording material P that has exited the nip between the heating roller 71 and the pressure roller 72 as indicated by an arrow W0. Separate from roller 71.

  Due to such air separation of the recording material P, the heated and high-temperature recording material P is separated by a non-contact separation means, so that it is due to the contact of the separation claws as compared with the case of using a commonly used separation claw. There is no degradation of image quality such as uneven wax.

  Reference numeral 110 denotes a curl detection sensor.

  As the curl detection sensor, a sensor that irradiates the recording material P with light, receives reflected light, and detects the distance between the sensor and the recording material can be used. Can be used.

  Instead of the curl detection sensor 110 or together with the curl detection sensor, a paper thickness detection sensor for detecting the thickness of the recording material P may be provided.

  As the paper thickness detection sensor, an optical sensor or the like that detects the distance between the sensor and the paper surface by irradiating light on the front and back surfaces of the recording material and receiving reflected light can be used.

  The recording material P passes through the nip between the heating roller 71 and the pressure roller 72 and is fixed, transported by the transport unit 100, and discharged from the paper discharge port 111 to the paper discharge tray 122.

  The conveyance unit 100 can be set by moving a part thereof as shown in FIGS. 4A, 4B, and 4C and FIGS. 5A, 5B, and 5C.

  In FIG. 4A, the fans 101A, 101B, and 101C and the belt units 102A, 102B, and 102C are arranged horizontally in the conveyance width direction, that is, perpendicular to the conveyance direction, and the belt units 102A, 102B, and 102C are planar conveyance surfaces S1. Form.

  In FIG. 4A, the recording material P is pressed against the belt units 102A, 102B, and 102C by the air flow indicated by V1 from the fans 101A, 101B, and 101C, and is transported while being held in a flat plate shape.

  In FIG. 4B, the fan 101A and the belt unit 102A on the right side of the drawing rotate around an axis parallel to the conveyance direction, and their right ends rise, and the fan 101C and the belt unit 102C on the left side of the drawing are parallel to the conveyance direction. Rotating about the axis raises these left edges. The central fan 101B and belt unit 102B are stationary in a horizontal state.

  In FIG. 4B, a concave conveyance surface S2 is formed at the center, and the recording material P is pressed against the belt units 102A, 102B, and 102C by the airflow indicated by V1 and V2 from the fans 101A, 101B, and 101C. Therefore, the recording material P is conveyed in a form in which the upper surface of the recording material P, that is, the central portion of the image carrying surface is concave.

  In FIG. 4C, the fan 101A and the belt unit 102A on the right side of the drawing rotate around an axis parallel to the conveyance direction, and the right ends thereof are lowered, and the fan 101C and the belt unit 102C on the left side of the drawing are parallel to the conveyance direction. Rotate around the axis and lower these left edges. The central fan 101B and the belt unit 102B remain stationary while being horizontal.

  In FIG. 4C, an upwardly convex return surface S3 is formed at the center, and the recording material P is pressed against the belt units 102A, 102B, and 102C by the airflow indicated by V1 and V3 from the fans 101A, 101B, and 101C. Therefore, the recording material P is conveyed in a form in which the upper surface of the recording material P, that is, the central portion of the image carrying surface is convex.

  The operation of the belt units 102A, 102B, and 102C will be further described with reference to FIG.

  The belt unit 102A includes rollers 103A and 104A that are arranged back and forth in the transport direction, and a belt 105A that is stretched around the rollers 103A and 104A.

  When forming the planar conveyance surface S1 shown in FIG. 4A, the axes of the rollers 103A and 104A are both in a horizontal state, and the belt 105A forms a horizontal planar conveyance surface.

  In the case where the concave conveyance surface S2 is formed in the upper portion at the center portion shown in FIG. 4B, the shaft of the roller 103A remains horizontal, but the shaft of the roller 104A is raised at the right end portion around the left end portion. Lean.

  The belt 105A is twisted by the inclination of the shaft of the roller 104A to form a horizontal conveyance surface on the upstream side close to the fixing device 7, but on the downstream side far from the fixing device 7, the inclined conveyance surface whose right end in the conveyance width direction is raised. Form.

  In the case where the upwardly convex conveying surface S3 is formed in the central portion shown in FIG. 4C, the shaft of the roller 103A remains horizontal, but the shaft of the roller 104A has the right end portion centered on the left end portion. Tilt down and lean.

  The belt 105A is twisted by the inclination of the roller 104A to form a horizontal flat conveyance surface on the upstream side close to the fixing device 7, but on the downstream side far from the fixing device 7, the right end portion in the conveyance width direction is inclined downward. Form a transfer surface.

  The belt unit 102B includes rollers 103B and 104B arranged side by side in the transport direction, and a belt 015B stretched around the rollers 103B and 104B.

  The belt unit 102B does not move as described above when forming the transport surfaces S1, S2, and S3 in FIG.

  The belt unit 102C includes rollers 103C and 104C that are arranged side by side in the transport direction, and a belt 015C that is stretched around the rollers 103C and 104C.

  In the case where the concave conveying surface S2 is formed in the upper portion at the center portion shown in FIG. 4B, the shaft of the roller 103C remains horizontal, but the shaft of the roller 104C is raised at the left end centering on the right end portion. Lean.

  The belt 105C is twisted by the inclination of the roller 104C to form a horizontal flat conveyance surface on the upstream side near the fixing device 7, but on the downstream side far from the fixing device 7, the left end portion in the conveyance width direction is inclined upward. Form a transfer surface.

  In the case where the upwardly convex conveying surface S3 is formed in the central portion shown in FIG. 4C, the shaft of the roller 103C remains horizontal, but the shaft of the roller 104C is centered on the right end portion and the left end portion is Tilt down and lean.

  The belt 105C is twisted by the inclination of the roller 104C to form a horizontal flat conveyance surface on the upstream side close to the fixing device 7, but on the downstream side far from the fixing device 7, the left end portion in the conveyance width direction is inclined downward. Form a transfer surface.

  FIG. 4 is a view of the belt units 102A, 102B, and 102C as viewed from the end on the downstream side in the conveyance direction, that is, the positions of the rollers 104A, 104B, and 104C.

  In this way, a horizontal and flat conveyance surface is held on the upstream side in the conveyance direction close to the fixing device 7, but on the discharge side far from the fixing device 7, as shown in FIG. Conveying surfaces S2 and S3 that are curved upward or concave are formed.

  In FIG. 2, the recording material P passes through the fixing device 7, is transported in the horizontal direction W <b> 1, and is discharged out of the apparatus from the paper discharge port 111.

  Curling is corrected by the conveyance in the state shown in FIGS. 4B and 4C and FIGS.

  In such correction, not only the curl of the recording material curved in the transport width direction is corrected, but also the curl curved in the transport direction is corrected by the transport unit 100 that forms the transport surfaces S2 and S3 curved in the transport width direction. It was confirmed that

  Furthermore, corrugation is imparted to the recording material by the conveyance shown in FIGS. 4B, 4 </ b> C, and 5 </ b> B and 5 </ b> C, and the recording material P is discharged to the paper discharge tray 122 in an orderly manner.

  The curl correction and corrugation imparted to the recording material P described above are performed without using a member in contact with the upper surface of the recording material P, that is, the image carrying surface, so that wax unevenness does not occur.

  Further, since the recording material is bent by air, it is also possible to avoid the recording material P from being streaked by corrugation.

  As shown in FIG. 4, even when the conveyance surface of the recording material is changed to S1, S2, and S3, the conveyance surface on the side close to the fixing device 7 is maintained in a horizontal flat shape as shown in FIG. Is done.

  Accordingly, the recording material is smoothly transferred from the fixing device 7 to the transport unit 100.

  FIG. 6 shows the conveyance unit 100 in a state in which the recording material P that has passed through the fixing device 7 is conveyed to the reverse conveyance unit 121.

  The conveyance unit 100 rotates about the axis of the roller 103B, and the fan 101B and the belt unit 102B rotate in a state inclined about 60 degrees counterclockwise from the horizontal direction as shown in the figure.

  The conveyance unit composed of the fan 101A and the belt unit 102B and the conveyance unit composed of the fan 101C and the belt unit 102C also rotate in the same manner as the conveyance unit composed of the fan 101B and the belt unit 102B.

  As a result, the transport path is switched, and the transport path enters a state in which the recording material P is transported to the transport roller 106, and the recording material P is transported in the downward W2 direction.

  The recording material P that has passed through the fixing device 7 is regulated by the air flow indicated by V4 by the fans 101A to 101C, changes its direction downward, reaches the conveying roller 106, and is conveyed downward by the conveying roller 106.

  The recording material P transported downward is transported upward by the transport roller 107 in reverse paper ejection, and then proceeds as shown by an arrow W3 to be ejected from the paper ejection port 112 to the paper ejection tray 122.

  Note that the paper discharge tray 122 descends to a position facing the paper discharge port 112 during reverse paper discharge.

  In the back side image formation, it proceeds as indicated by an arrow W4 and is conveyed to the refeed unit 120 (see FIG. 1).

  Reference numeral 108 denotes a gate for switching and guiding the recording material P to the paper discharge port 111 or the refeeding unit 120. When the recording material P is conveyed in the direction indicated by the arrow W2, the recording material P is guided in the state indicated by the solid line, and the arrow W3 is indicated. When the recording material P is conveyed in the direction indicated by, the recording material P is tilted to the left as shown by a dotted line 108A to guide the recording material P, and when conveying the recording material P as indicated by the arrow W4, as indicated by a dotted line 108B. Then, the recording material P is guided to the right.

  Also in the switching of the conveyance path shown in FIG. 6, it is the air flow V4 that guides the recording material P from the horizontal direction to the downward direction, and the conveyance guide is performed without contact with the image carrying surface of the recording material P. Unevenness can be avoided.

  7 moves the transport unit 100 to the state shown in FIGS. 4A, 4B, 5C, 5A, 5B, and 5C, and the state shown in FIG. 6 shows a mechanism for moving to the state shown in FIG.

  The transport unit 100 is provided so as to be rotatable about a shaft 100 </ b> A provided in the lower part thereof, and the transport unit 100 is rotated via the gear 116 by driving of the motor 115.

  That is, as shown in FIG. 2, the fans 101A to 101C and the belt units 102A to 102C rotate from a horizontal state so that the paper discharge port side is downward as shown in FIG.

  The shaft of the belt unit 102B at the center in the conveyance width direction does not move from the horizontal state.

  On the other hand, the shaft 102AX of the belt unit 102A is attached to the left end in FIG. 7 so as to be rotatable about an axis parallel to the transport direction.

  A rack 115A is provided at the right end of the shaft 102AX, and the rack 115A meshes with a gear 114A driven by a motor 113A.

  Similarly, the shaft 102CX of the feeding unit 102C is attached to the right end in FIG. 7 so as to be rotatable about an axis parallel to the transport direction.

  A rack 115B is provided at the left end of the shaft 102CX, and the rack 115B meshes with a gear 114B driven by a motor 113B.

  By driving the motors 113A and 113B, the shaft 102AX rotates and tilts around its left end, and the shaft 102CX rotates and tilts around its right end.

  By such driving of the motors 113A and 113B, the transport knits 102A and 102C are changed from the horizontal state in FIG. 4A to the reverse letter C shape in FIG. It becomes.

  The fans 101A and 101C are also moved to the states shown in FIGS. 4A, 4B, and 4C by the same drive mechanism.

In the discharge of the recording material P, the appropriate discharge conditions vary depending on the properties of the recording material P and the image to be formed, and appropriate discharge is performed mainly by changing the discharge conditions due to the following factors.
(1) Curling of the recording material (2) Thickness of the recording material When the recording material is thin, it is preferable that the recording material is curved in the conveyance width direction to give straightness and discharged.
(3) Environment In the case of high temperature and high humidity, it is the same as when the recording material is thin.
(4) Black and white image / color image In a color image, the thickness of the toner image forming the image is thick, and the image quality tends to be lowered due to contact with the image, and high image quality is required. Therefore, it is preferable to discharge the image while avoiding as much as possible the contact of the image with various parts of the conveying device.

  For example, when ejecting a recording material having an image bearing surface that is convexly curled at the central portion, as shown in FIG. However, in the case of the opposite curl, a condition for discharging the paper after performing curl correction that is convex at the center as shown in FIG. 4C is set.

  A preferable setting condition of the conveyance unit 100 for various conditions can be obtained in advance by experiments, and the conveyance unit 100 is set using the obtained results.

  FIG. 8 is a block diagram of a control system in the embodiment of the present invention.

  CR is a control means, 110 is a curl detection sensor for detecting curl of the recording material, TS is a paper thickness detection sensor for detecting the thickness of the recording material, ES is an environment detection sensor, MS is set in color mode or monochrome mode NM is a nonvolatile memory, 113A and 113B are the motors described above.

  As described above, the non-volatile memory NM stores a correspondence table of setting conditions of the motors 113A and 113B with respect to input information from the curl detection sensor 110, the paper thickness detection sensor TS, the environment detection sensor ES, and the mode setting unit MS. ing.

  The correspondence table stores a program for changing the conveyance surface corresponding to information from at least one of the car detection sensor 110, the paper thickness detection sensor TS, the environment detection sensor ES, and the mode setting unit MS. The control means CR controls the motors 113A and 113B according to this program to change the conveying surface as shown in FIGS.

  The control means CR also controls the motors 114A and 114B based on the setting information in the mode setting unit MS to change the conveying surface as shown in FIG.

  As described above, the motors 113A and 113B drive the belt units 102A and 102C, but also drive the fans 101A and 101C, as shown in FIGS. 4 (a), 4 (b), and 4 (c). The conveyance unit 100 is set as follows. Note that FIG. 4 shows an example of setting, and an intermediate conveyance state is set between (a), (b), and (c), and an optimal conveyance surface is set for various conditions.

  The control means CR further controls the driving of the motor 115 in reverse paper discharge and backside image formation, and switches the conveyance path from FIG. 2 to FIG.

1 is a diagram illustrating a color image forming apparatus according to an embodiment of the present invention. 2 is a front cross-sectional view of a fixing device 7 and a conveyance unit 100 according to an embodiment of the present invention. FIG. FIG. 3 is a plan sectional view of the fixing device 7 and the conveyance unit 100 in the embodiment of the present invention. It is a side view of the conveyance part 100 in embodiment of this invention seen from the paper discharge outlet side. 3 is a perspective view of a part of the fixing device 7 and a conveyance unit 100. FIG. The conveyance unit 100 in a state where the recording material P that has passed through the fixing device 7 is conveyed to the reverse conveyance unit 121 is shown. It is a figure which shows the mechanism which moves the conveyance part 100 to the state shown to Fig.4 (a), (b), (c), and moves to the state shown in FIG. 2, and the state shown in FIG. It is a block diagram of a control system in an embodiment of the present invention.

Explanation of symbols

7 Fixing Device 50 Image Forming Unit 100 Conveying Unit 101A, 101B, 101C Fan 102A, 102B, 102C Belt Unit CR Control Unit 110 Curl Detection Sensor TS Paper Thickness Detection Sensor ES Environment Detection Sensor

Claims (5)

In an image forming apparatus including an image forming unit that forms an image on a recording material, a fixing device that fixes an image on the recording material, and a conveyance unit that conveys the recording material discharged from the fixing device.
The transport unit includes a transport unit that supports and transports the recording material, and a fan that is provided to face the transport unit and generates an airflow toward the transport unit, and is arranged in parallel in the transport width direction. Having a transport unit ,
The conveyance surface of the recording material is changed by forming a conveyance surface curved in the conveyance width direction by tilting a part of the conveyance unit arranged at the end in the conveyance width direction. Image forming apparatus. The transport unit has a plurality of rollers arranged side by side in the transport direction and a belt stretched around the rollers, and the curved transport surface is formed by tilting a part of the shaft of the rollers. The image forming apparatus according to claim 1 . 3. The image forming apparatus according to claim 1, wherein when the transport surface is changed, the transport surface closer to the fixing device is maintained in a flat plate shape. Before Ki搬 transmission unit rotates about an axis parallel to the conveying width direction, the image forming apparatus according to claim 1, characterized in that the conveying path for conveying is switched to the recording material. Either a curl detection sensor that detects the curl of the recording material, a paper thickness detection sensor that detects the thickness of the recording material, an environment detection sensor that detects at least one of temperature and humidity, and a setting unit that sets the type of the recording material Having at least one and control means;
The control means is arranged at the end in the transport width direction based on information from at least one of a curl detection sensor of the recording material, the paper thickness detection sensor, the environment detection sensor, and a setting unit. The image forming apparatus according to claim 1 , wherein the conveyance surface is changed by inclining a part of the conveyance unit to form the conveyance surface curved in the conveyance width direction .

Images