JP2007160879A - Image recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform highly precise paper conveyance by suppressing a variation in resistance that is caused when a rear end of paper escapes from a paper feeding roller or caused by influence of curling in an ink-jet recording apparatus. <P>SOLUTION: The apparatus has a conveyance roller for conveying paper to a recording unit, a paper feeding roller disposed in the upstream-side of the conveyance direction for conveying the paper to the conveyance roller, and a guide member disposed between the two rollers for guiding the paper. A resistance means for adjusting the paper into the shape of the guide by applying resistance to the paper by a fan is disposed between the conveyance roller and the paper feeding roller. The ink-jet recording apparatus has a control means for controlling drive of the fan. When the rear end of the paper escapes from the paper feeding roller, the fan is driven by the control means to apply resistance to the paper. The fan is kept driven after the rear end of the paper escapes from the paper feeding roller, and conveyance of the paper is continued in the state that the paper is adjusted in the shape of the guide. When the rear end of the paper gets close to the conveyance roller, conveyance of the paper is stopped to stop the fan, and the resistance of the paper is canceled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image recording apparatus that separates and feeds sheets one by one from a stacked sheet bundle, and further conveys the sheet downstream by a sheet feeding roller to record an image.

2. Description of the Related Art Conventionally, there is an apparatus that records an image with ink after a sheet feeding roller comes into contact with the upper surface of a stacked sheet bundle and feeds one sheet, and further, the sheet is conveyed to the front of a recording head by a conveyance roller. In this apparatus, when the transport roller starts to transport the paper, the rear portion of the paper still remains under the paper feed roller, so that resistance acts by the frictional force between the paper feed roller and the paper. For this reason, when the trailing edge of the paper comes out of the paper feed roller, the resistance acting on the paper sharply decreases, and the problem arises that the amount of paper feed varies and the recorded image is disturbed. In order to prevent this, there is a configuration in which a film-like resistance member is disposed between the paper feed roller and the transport roller to suppress a rapid fluctuation in resistance acting on the paper (see Patent Document 1).
Japanese Patent Laid-Open No. 10-095549 (FIG. 6)

  However, the prior art has the following problems.

  In the prior art, a rapid resistance when the trailing edge of the paper leaves the paper feed roller is suppressed by providing a film-like resistance member between the paper feed roller and the transport roller. However, when the trailing edge of the sheet passes through the film member, although smaller than when the trailing edge of the sheet passes through the paper feed roller, there remains a problem that resistance variation occurs as in the conventional problem.

  In addition, large-format ink jet printer devices that can be used for printing posters and the like are currently being manufactured. These devices must be able to record images with high accuracy on various types of paper, such as thick paper that can be used for poster printing and thin paper such as Japanese paper, as well as plain paper that has been commonly used. I must. Among the papers used in these large-format inkjet printers, there are types of papers that are easily deformed into a curl shape, and types of papers that curl in a high temperature and high humidity environment. In the case of recording an image on these sheets, there is a problem that resistance fluctuation due to the curl shape occurs in addition to the above-described fluctuation when the trailing edge of the paper passes through the paper feed roller. That is, with the momentum that the trailing edge of the paper has passed through the paper feed roller, the resistance variation caused by the curling portion that has occurred at the trailing edge of the paper strongly hitting the guide, or the curled shape portion remains in strong contact with the guide There is a problem that resistance is generated by being conveyed.

  This patent was made in view of the above problems, and suppresses a rapid decrease in resistance that occurs when the trailing edge of the paper comes off from the paper feed roller, and a variation in resistance that occurs due to the effect of curling that has occurred on the paper. This makes it possible to perform high-precision paper conveyance.

  The present invention that solves the above-described problems includes a recording unit that records image information with ink on a sheet, a first conveying unit that conveys the image to the recording unit, and an upstream side in the conveying direction with respect to the first conveying unit. A second conveying means, and a guide means arranged between the first conveying means and the second conveying means for guiding the sheet conveyed from the second conveying means to the first conveying means. An ink jet recording apparatus having an ink jet recording apparatus disposed between the first transport unit and the second transport unit, wherein the sheet is transported between the first unit and the second unit in the transport direction. It has a resistance means for giving resistance to the means and a means for making the shape of the guide means, and the resistance means also serves as a means for making the shape of the guide means.

  In addition, the present invention is characterized by comprising control means for controlling the magnitude of the resistance.

  Further, in the present invention, while the sheet is being conveyed by both the first conveying means and the second conveying means, the resistance by the resistance means is not given, and the trailing edge of the sheet has the second conveying means. When the sheet is pulled out, it is controlled by the control means so as to give resistance to the sheet by the resistance means.

  Further, in the invention, while the trailing edge of the sheet passes through the second conveying unit and is conveyed by the first conveying unit, the resistance unit continuously applies resistance to the sheet unit, and the first conveying unit When the conveyance is stopped by the control, the control means controls the resistance by the resistance means to stop.

  Further, the present invention is characterized in that the resistance means generates resistance by sucking the sheet by a fan, or generates resistance by discharging exhaust from the fan to the sheet.

  As described above, in the ink jet recording apparatus of the present invention, the first roller for transporting the sheet to the recording unit, the second roller means arranged on the upstream side in the transport direction, the first roller and the first roller A guide means disposed between two rollers, a means for causing the sheet to conform to the shape of the guide means with respect to the guide means, and a resistance means for giving resistance to sheet conveyance by the means Doubles as When the rear end of the sheet comes off from the first roller member, the resistance is applied to the sheet by the resistance means to suppress a sudden change in load, and the rear end of the sheet is between the first roller and the second roller. When the sheet is conveyed, the resistance means causes the trailing edge to be conveyed along the guide shape, thereby suppressing load fluctuations due to curling. Further, after the conveyance is temporarily stopped, the resistance means is stopped so that the sheet trailing edge is the resistance. By suppressing the fluctuation of the load that occurs when exiting the means, it is possible to stably convey the sheet and record an image with high accuracy.

Example 1
An embodiment of a recording apparatus according to the present invention to which the above means is applied will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an ink jet recording apparatus to which the present invention is applied, FIG. 2 is a front perspective view of a recording unit, and FIG. 3 is a rear perspective view of the recording unit.

  First, the schematic configuration of the apparatus will be described with reference to FIG. The recording apparatus mainly includes a sheet feeding unit that separates and conveys one sheet from a stacked sheet bundle, a recording unit that records an image with ink on the conveyed sheet, a housing cover member that covers the entire apparatus, a recording It consists of a control unit that controls the operation of the entire apparatus, and a power source.

  In FIG. 1, 1 is a cassette for storing stacked sheet bundles, 2 is an upper cover that covers the top of the housing, 3 is a rear cover, and 4 is a sheet that is discharged after being recorded by ink and stacked. It is a tray.

  The flow of the recording paper P will be described. The recording paper conveyance path is indicated by an arrow G in the drawing.

  The sheet feeding unit is composed of a cassette 1 and a pickup roller 11, a feed roller 12 and a retard roller 13 which are stacked at the lower part of the apparatus with the sheet material P stacked thereon. The sheet feeding unit picks up the sheet material one by one and feeds it to the main body. A paper feed mechanism is provided. The sheet material sent by the paper feeding mechanism passes through the intermediate roller 14 and the intermediate roller 15 and is sent to the recording unit by the conveying roller 16 and the pinch roller 17. Recording is performed by a recording head 42 serving as recording means, and after being transported within a certain distance in the apparatus, it is discharged and stacked on the discharge tray 4 by a discharge roller 18 and a spur 19.

  The paper feeding unit will be described. The drive unit for the pickup roller 11 and the feed roller has a transmission unit for transmitting a driving force from a conveyance motor (not shown) which is a driving unit in the main body and a release unit for releasing the driving force. The driving force from the conveying motor is transmitted to the feed roller 12 at the same time as the pickup roller 11 and starts rotating.

  The feed roller 12 is driven in the direction of arrow A by a driving means in the main body. The retard roller 13 is attached with a torque limiter (not shown). The retard roller 13 is provided with an elastic means for applying a constant pressure to the feed roller and a release means for releasing the elastic means, and the retard roller 13 applies a constant pressure to the feed roller 12 during the sheet separation operation. The state is energized by pressure.

  When a certain torque is applied to the retard roller 13 in the arrow B direction, the torque limiter slips and the retard roller 13 rotates in the arrow B direction. The retard roller 12 stops when it is below a predetermined constant torque, and when more torque is applied in the transport direction, the retard roller 12 is rotated in the transport direction by the torque. The predetermined torque is hereinafter referred to as T.

  When there is no sheet between the feed roller 12 and the retard roller 13 or when one sheet material is nipped, the torque T of the retard roller is compared with the torque applied from the feed roller 12 to the retard roller 13. Since it is set small, the retard roller 12 is driven by the feed roller 12 and rotates in the transport direction.

  When two or more sheets enter the nip, the torque due to the friction between the plurality of sheets is set smaller than the torque T of the retard roller 12, so the retard roller does not rotate (still stopped), The sheet on the side in contact with the retard roller is not conveyed.

  By the above operation, the sheet material fed by the pickup roller 11 is separated into only the uppermost sheet and conveyed.

  The conveyed sheet is guided and conveyed by the U-turn guide 31 and the U-turn outside guide 32. The sheet conveyed from the bottom to the top of the apparatus by the U-turn guide is changed in the horizontal direction toward the front of the apparatus. An intermediate roller 14 is disposed at a position where the sheet conveyance direction changes to the front of the apparatus. The intermediate roller 14 is connected by a conveyance motor and a transmission means, and rotates according to the driving of the motor. An intermediate roller 15 is disposed on the opposite side of the intermediate roller 14. The intermediate roller 15 is pressed against the intermediate roller 14 by elastic means so as to be freely rotatable, and rotates following the intermediate roller 15. A jam sensor 21 is disposed between the intermediate roller 14 and the feed roller 12.

  An edge sensor 22 that detects the leading edge and the trailing edge of the recording paper is disposed downstream of the intermediate roller 14 in the conveyance direction. Further downstream, a conveying roller 16 that conveys the sheet to the recording unit and a pinch roller 17 are arranged at a position opposite to the conveying roller 16.

  The conveyance roller 16 is connected to a conveyance motor (not shown) as a driving source by a transmission means, and rotates according to the driving of the motor. The pinch roller 17 is located at a position facing the conveyance roller 16 and is pressed against the conveyance roller 16 by an elastic means so as to be rotatable.

  Here, the conveyance speed of the conveyance roller 16 and the conveyance speed of the intermediate roller 14 will be described. The paper transport speed of the transport roller 16 is set to be slightly higher than the paper transport speed of the intermediate roller 14. If the conveying speed of the conveying roller 16 is slower than the conveying speed of the intermediate roller 14, a loop occurs in the sheet as the sheet is conveyed. When the loop becomes large, the tip of the enlarged loop comes into contact with the U-turn outer guide 32 or the U-turn guide 31 and the load applied to the conveyance roller fluctuates, and the conveyance amount becomes unstable. In order to prevent the problem, the conveying speed of the conveying roller 16 is set to be slightly higher than the conveying speed of the intermediate roller 14. The conveying force of the conveying roller 16 is set to be larger than the conveying force of the intermediate roller 14, and the sheet is conveyed by the conveying roller 16 while slightly sliding with respect to the intermediate roller 14.

  Next, the configuration of the recording unit will be described with reference to FIGS. In FIG. 2, the recording head 42 of this embodiment is equipped with a cartridge type recording head that can be replaced with a new one.

  The recording head 42 used in this embodiment is an ink jet recording head, has a nozzle row in which nozzles for ejecting ink are arranged in a row, and is generated in the ink due to heat generated by an electrothermal conversion element provided in the nozzle. Ink is discharged from the discharge port at the tip of the nozzle by the pressure of film boiling. Reference numeral 41 denotes a carriage for reciprocally moving in the main scanning direction (arrow H direction) perpendicular to the conveyance direction (sub-scanning direction, arrow G direction) of the recording paper P while holding the recording head 42 with high accuracy. Yes, it is slidably held by a guide bar 43 and an abutting portion (not shown). The reciprocating movement of the carriage 41 is performed by a pulley 45 and a timing belt 46 driven by a carriage motor (not shown). At this time, a recording signal and power applied to the recording head 42 are transmitted from an electric circuit of the apparatus main body by a flexible cable 47. Have been supplied. The flexible cable 47 is attached to a substrate (not shown) disposed on the carriage 41, and the recording head 42 and the carriage 41 are connected by press-contacting the contacts.

  Further, the carriage 41 is installed corresponding to a standby position (home position), and moves up and down as necessary. When the carriage 41 is raised, the carriage 41 is in close contact with the recording head 42 and covers the nozzle portion to prevent ink evaporation and dust adhesion. A cap that functions as an ink receiving means is disposed at the right end of the apparatus (not shown).

  An encoder sensor 48 is attached to the carriage 41, and a scaler 44 is disposed at a position corresponding to the encoder sensor 48. The scaler and encoder sensor 48 detect the position of the recording head 42 in the main scanning direction.

  The paper discharge roller 18 is driven by a transport motor (not shown). Reference numeral 19 denotes a spur, which is made of a material having high water repellency, and is in contact with the sheet only by the recording paper surface and the blade-shaped circumferential portion. The spurs 19 are arranged at a position facing the paper discharge roller 6 at a plurality of locations separated by a predetermined length in the main scanning direction by a bearing member (not shown), and contact the unfixed image on the recording paper immediately after recording. However, the recording paper P is guided and conveyed without affecting the image. A platen 33 facing the head 42 and disposed between the transport roller and the paper discharge roller 188 guides a sheet sent from the transport roller 16 and printed.

  Next, the configuration of the suction duct 51 will be described. FIG. 4 is a perspective view around the duct. In the apparatus according to this embodiment, a suction duct 51 is disposed below the platen 33 and the U-turn guide 31. A suction fan 53 is disposed below the duct and is connected to a control unit in the main body. The upper surface of the suction duct 51 is attached to the flat portions of the platen 53 and the U-turn guide 31. A plurality of rows of platen suction ports 33a are arranged in the sub-scanning direction on the upper surface portion of the platen 33 (two rows of holes are arranged in the sub-scanning direction in the apparatus of this embodiment). A duct suction port 51a is arranged at a position corresponding to the above. The U-turn guide 31 is also provided with a plurality of rows of suction ports 31a on the surface in close contact with the suction duct 41 (three rows of suction ports 31a are arranged in the apparatus of this embodiment), and the U-turn A duct suction port 51 b is disposed at a position corresponding to the suction port 31 a of the guide 33. On the side of the suction duct 51, an exhaust port 51C for discharging the air sucked by the platen fan 53 to the outside of the duct is arranged.

  In the suction duct 51, a suction switching valve 52 is disposed that completely separates between the platen 33 side and the U-turn guide 33 side. The suction switching valve 52 has a shaft 52a that extends laterally and is attached to the side surface of the suction duct 51, and can rotate 90 degrees around the shaft 52a. The tip of the shaft 52a is connected to a solenoid (not shown). When the solenoid is OFF, the suction switching valve 52 is at the position C in the figure, and acts as a threshold separating the inside of the suction duct 51 into the U-turn guide side and the platen side. Therefore, even if the suction fan 53 is rotated when the switching valve 52 is at the position C, suction is not performed from the suction port 31a.

  When the solenoid is turned on, the suction switching valve 52 rotates 90 degrees around the shaft 52a and moves to the position D in the figure, and the thresholds on the U-turn guide 31 side and the platen 33 side disappear. When the suction fan 53 rotates at this time, suction is performed from the suction port 31 a of the U-turn guide 31. When the power source connected to the solenoid is turned off, the switching valve 52 returns to the position C in the figure again.

  Accordingly, when the platen fan 53 is rotated while the sheet is being conveyed and the suction switching valve 52 is in the position D (when the solenoid is turned on), the sheet is sucked into the suction port 31a of the U-turn guide 31. Then, the U-turn guide 33 is conveyed in a state along the shape. In this case, conveyance resistance due to suction occurs.

  Next, the control unit of the apparatus of this embodiment will be briefly described.

  The control unit is used to control the entire recording apparatus, and is used as a CPU such as a microprocessor, a ROM that stores a CPU control program and various data, and a work area of the CPU, and temporarily stores various data. It has a RAM for storage. A carriage motor (not shown), a conveyance motor (not shown), a platen fan 53, a solenoid (not shown), a drive circuit for each motor and various sensors are connected to the control unit. The motor and solenoid are driven according to commands from the control unit.

  Next, a conveying operation when recording an image on a sheet will be described with reference to FIG.

When an image recording command is received from a computer connected to the recording apparatus, the CPU drives a transport motor in the main body. The pickup roller 11 rotates and contacts the uppermost part of the sheets stacked on the cassette 1. (Fig. 5a)
At this time, simultaneously with the rotation of the pickup roller 11, the feed roller 12, the intermediate roller 14, the transport roller 16, and the paper discharge roller 18 that are connected by the transfer means from the transport motor also start to rotate. By the action of the feed roller 12 and the retard roller 13, the uppermost one of the sheets fed by the pickup roller 11 is separated and conveyed. When the leading edge of the sheet is detected by the jam sensor 21 and is nipped between the intermediate roller 14 and the intermediate roller 15, the driving of the feed roller 12 is released by the releasing means, and the elastic means that pressurizes the retard roller 13 is also released. Released by means. When the sheet is conveyed by the intermediate roller 14 and the intermediate roller 15 and the leading edge of the sheet is detected by the edge sensor 22, the platen fan 53 is driven to start suction from the platen suction port 33a (at this time, the suction switching valve 52 is In position C). (Fig. 5b)
The leading edge of the sheet is nipped between the conveyance roller 16 and the pinch roller 17 and conveyed onto the platen 33. At this time, the sheet is conveyed while being sucked on the platen suction port 33a. When the sheet is conveyed to the image printing position, the conveyance motor is stopped and the conveyance of the sheet is stopped. Next, the carriage motor is driven, and the carriage 41 and the recording head 42 are moved while ejecting ink in the main scanning direction to record an image (the recording head 42 is driven in the main scanning direction to perform a printing operation). The width in the sub-scanning direction for printing in one operation is hereinafter referred to as one line). When the recording of one line is completed, the conveying motor is driven again, the conveying roller 16 is rotated by one line, and the sheet is conveyed. When the conveying roller 16 is rotated by one line, the driving of the conveying motor is stopped, and then the recording operation for one line is performed. The above series of operations of conveyance → stop → recording is repeated for each line to record an image. In the above series of operations, the conveyance operation is performed, and when the trailing edge of the sheet is detected by the jam sensor 21, the solenoid is turned on during the next stop operation, and the suction switching valve 52 rotates 90 degrees to achieve D. (Fig. 5c).

  The series of operations is repeated again for each line, and an image is recorded. Therefore, when the trailing edge of the sheet passes through the nip between the intermediate roller 14 and the intermediate roller 15, the trailing edge of the sheet is conveyed while being sucked by the suction port 31 a of the U-turn guide 31.

Further, when the edge sensor 22 detects the trailing edge of the sheet during the conveyance operation, the solenoid is turned off at the next stop operation, the suction switching valve 52 is rotated 90 degrees and returned to the position C, and the suction of the U-turn guide 31 is performed. Suction from the mouth 31a is stopped. Thereafter, the next recording operation is performed, and the series of operations are repeated for each line to record an image. (Fig. 5d)
As described above, in the apparatus of this embodiment, when the sheet trailing edge passes through the nip between the intermediate roller 14 and the intermediate roller 15, the platen fan 53 is rotated to suck the sheet from the suction port 31a of the U-turn guide 31. Thus, resistance is given to reduce abrupt fluctuation when exiting the nip. When the sheet trailing edge is between the intermediate roller 14 and the conveying roller 16, the sheet trailing edge 53 is conveyed along the shape of the U-turn guide 31 by the rotation of the platen fan 53. Further, the suction operation from the suction port 31a of the U-turn guide 31 is stopped when the sheet conveyance is stopped, thereby suppressing the variation in the conveyance speed.

(Example 2)
The device configuration of this patent is different from the device configuration of the first embodiment only in the configuration of the suction duct and the U-turn guide. However, the U-turn guide of the second embodiment is different from the configuration of the first embodiment only in that the suction port 31a does not exist, and the others are the same. Therefore, hereinafter, the structure of the suction duct will be described.

  A schematic cross-sectional view of the apparatus of Example 2 is shown in FIGS.

  A suction portion of the suction duct 61 is disposed below the platen 33, and a platen fan 53 is disposed below the suction duct 61. The upper surface of the suction duct 61 is attached in close contact with the platen 33, and the duct suction port 61a is disposed at a position corresponding to the platen suction port 33a. The tip of the exhaust port of the platen fan 53 extends between the intermediate roller 15 and the pinch roller 17 and above the U-turn guide 31, and forms a part of the U-turn outer guide 32. A plurality of rows of guide exhaust ports 61b, which are small-diameter holes, are arranged on the surface facing the U-turn guide 31.

  In the suction duct 61, there is an exhaust path switching valve 62. The exhaust path switching valve 62 has a rotary shaft 62a on its side surface, and the rotary shaft 62a is attached to the side surface of the suction duct 61. It is possible to rotate 90 degrees around 62a. The exhaust path switching valve 62 is connected to a solenoid (not shown). When the solenoid is OFF, the exhaust path switching valve 62 is disposed at a position where the exhaust from the platen fan 53 is directly discharged from the exhaust port 61c to the outside of the duct (FIG. 6). At this time, the flow of air sucked from the platen fan 53 is indicated by an arrow E, and the flow of air discharged from the platen fan 53 to the outside of the duct is indicated by an arrow F.

  When the solenoid is turned on, the exhaust path switching valve 62 rotates 90 degrees around the rotation shaft 62a and closes the exhaust port 61c (FIG. 7). The path of the air discharged from the platen fan 53 at that time is indicated by an arrow J. The air discharged from the platen fan 53 is discharged toward the U-turn guide 31 from the guide exhaust port 61 located above the U-turn guide 31. Accordingly, when the solenoid is turned on while the sheet is being conveyed on the U-turn guide 31, the exhaust path switching valve 62 moves to block the duct exhaust port 62, and the exhaust from the platen fan 53 is guided to the guide exhaust port 61c. The sheet is blown onto the sheet, and by the force, the sheet is conveyed in a state along the guide shape. At that time, conveyance resistance is caused by the discharged air.

  As described above, in the first embodiment, the function of causing the sheet conveyed on the U-turn guide to follow the guide shape by the suction means and the resistance for suppressing a rapid decrease in the resistance when the trailing edge is pulled out from the intermediate roller. A control function is realized. In the second embodiment, an exhaust means is used instead of the suction means of the first embodiment, and the function of conveying the sheet in a guide shape by the exhaust from the fan and the resistance control function are realized. is doing.

FIG. 2 is a schematic sectional view of the recording apparatus shown in the first embodiment. Front perspective view of recording unit Rear perspective view of recording unit Perspective view around the duct Diagram showing operation during recording FIG. 3 is a schematic cross-sectional view of the recording apparatus shown in the second embodiment. FIG. 6 is a schematic cross-sectional view illustrating a state during operation of the recording apparatus illustrated in the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cassette 2 Case top cover 3 Back cover 4 Paper discharge tray 11 Pickup roller 12 Feed roller 13 Retard roller 14 Intermediate roller 15 Intermediate roller 16 Conveyance roller 17 Pinch roller 18 Paper discharge roller 19 Spur 21 Jam sensor 22 Edge sensor 31 U-turn Guide 32 U-turn outside guide 33 Platen 41 Carriage 42 Recording head 43 Guide bar 45 Pulley 46 Timing belt 47 Flexible cable 48 Encoder sensor 49 Scaler 51 Suction duct 52 Suction switching valve 53 Discharge port 53 Platen fan 61 Suction duct of the second embodiment 62 Exhaust path switching valve P seat

Claims (6)

A recording means for recording image information with ink on a sheet; a first conveying means for conveying to the recording means; a second conveying means arranged on the upstream side in the conveying direction with respect to the first conveying means; A guide unit that is disposed between the first transport unit and the second transport unit and guides the sheet transported from the second transport unit to the first transport unit;
A resistance unit that is disposed between the first transport unit and the second transport unit, and that gives resistance to a transport direction when the sheet is transported between the first unit and the second unit; An ink jet recording apparatus comprising: means for making the shape of the guide means, and the resistance means also serving as means for making the shape of the guide means.   2. The ink jet recording apparatus according to claim 1, wherein the resistance means includes control means for controlling the magnitude of the resistance. While the sheet is being conveyed by both the first conveying means and the second conveying means, the resistance by the resistance means is not given,
3. The ink jet recording apparatus according to claim 2, wherein when the trailing edge of the sheet exits the second conveying unit, the control unit controls the resistance unit to apply resistance to the sheet.   While the trailing edge of the sheet passes through the second conveying means and the sheet is conveyed by the first conveying means, the resistance means continues to give resistance to the sheet means, and the first conveying means 4. The ink jet recording apparatus according to claim 3, wherein the control means controls the resistance by the resistance means to stop when the conveyance is stopped.   5. The ink jet recording apparatus according to claim 4, wherein the resistance means is resistance caused by sucking the sheet by a fan.   5. The ink jet recording apparatus according to claim 4, wherein the resistance means is resistance caused by exhausting air from the fan to the sheet.

Images