JPS63180668A - Sheet curl removing device - Google Patents

Abstract

PURPOSE:To improve the arrangement performance of a sheet by correcting the curl on the sheet at each part at an arbitrary time by varying the correction quantity of a curl correcting means by a correction quantity varying means according to the curl quantity at each sheet part which is detected by a curl quantity detecting means. CONSTITUTION:When a sheet S on which curl is generated through fixation is guided into a curl quantity detecting device 36 from the transport inlet of a stacker device, and contacts a lever 39, the lever 39 turns in accordance with the curl quantity, and one edge 39a cuts off several parts among a pluralty of detection parts 40a of a sensor 40, and the signal corresponding to the curl quantity is outputted into a control part 41. The control part 41 varies the pressing force for a roller shaft 19 of a cam 31 by controlling the revolution of a cam motor 33, and attaches a plurality of rollers 30 made of spnge material onto an opposed crown-shaped driving roller 21 made of rubber material according to the curl quantity, and corrects the curl on the sheet S. Therefore, the arrangement performance of the sheet call be improved.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention is used in an image forming bag M (hereinafter referred to as a copying machine) for a copying machine, a printing machine, a laser beam printer, etc., and is used to remove curling of a sheet. The present invention relates to a curl removal device, and more particularly to a curl removal device that straightens curls according to the amount of curl in each portion of a sheet.

(B) Prior Art Conventionally, a tcosheet having an image copied thereon by a copying machine has the image fixed thereon by heat and pressure in a fixing device, and then is discharged onto a discharge tray by a discharge device.

←→ Problems to be Solved by the Invention By the way, in the above-mentioned copying machine, since the image on the sheet is fixed by heating and pressurizing in the fixing device, warpage occurs in the sheet 1-, resulting in a curled sheet. In many cases, when the curled sheets are collected on a discharge tray, the alignment of the sheets is significantly deteriorated. Further, when a curled sheet is processed by a sheet post-processing device, stable processing cannot be performed due to the warping of the sheet.

Therefore, a curl removing device has been devised in which a curl correction means for removing the curl of the sheet 1- is disposed on the sheet 1- conveying path. is detected, and the curl of the sheet is corrected by the same amount of correction from the leading edge of the sheet to the trailing edge based on the detection signal of the curl amount detecting means, so that even the part where there is no curl is corrected and curled in the opposite direction. This caused poor sheet loading consistency.

(b) Means for Solving the Problem The present invention aims to solve the above-mentioned problems, and includes a curl amount detection means for detecting the amount of curl of the sheet in each portion of the sheet, and a curl amount detection means disposed downstream of the curl amount detection means. a curl correction means for correcting the curl of the sheet, and a correction amount changing means for receiving a detection signal from the curl amount detection means and changing the correction amount of the curl correction means, the correction amount changing means The present invention is characterized in that the means is configured to change the amount of correction by the curl correction means in accordance with the amount of curl in each portion of the sheet detected by the curl amount detection means.

(E) Operation Based on the above-described configuration, when a curled sheet is conveyed to the curl amount detection means, the curl amount detection means detects the curl amount of each portion of the sheet, and transmits a detection signal to the correction I change means. . The correction amount changing means corrects curls in each portion of the sheet by changing the curl correction amount of the curl correction means as needed based on the detection signal of the curl amount detection means.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the copying machine 1 has a paper feeding section and a copying section (both not shown) in the main body 2, and downstream of the copying section, a fixing device 3 and a pair of ejection rollers. 5 are arranged. A stacker device 6 is disposed in the copying machine main body 2, and the loading lower of the stack M6 and the discharge port 9 of the copying machine main body 2 are arranged at the same horizontal position. Further, a flapper 10 is disposed downstream of the carry-in lower,
A curl straightening device 11 is disposed downstream of the seven wrapper 10. Further, downstream of the device 11, there is a
A group of discharge rollers 512 for discharging the paper is disposed, and a refeed path 13 is also disposed branching off from the seven ranopas 10. A stacker tray 16 for stacking sheets 1-S is supported on the side of the stacker main body 15 so as to be movable up and down.

Further, in the curl straightening device 11, as shown in detail in FIGS. 2 and 3, the drive shaft 17 is connected to the stacker device main body 1.
A roller shaft 19 is supported so as to be freely rotatable and axially movable by the drive shaft 17, and a cam shaft 20 is supported substantially parallel to the drive shaft 17 so as to be movable in the vertical direction. is rotatably supported. Furthermore, a crown-shaped roller 21 made of rubber material is fixed to the drive shaft 17, and a gear 22 is splined to one end of the drive shaft. The stacker device main body 1 is attached to one end A of the drive shaft 17.
A spring 23 fixed to one end B is in contact with the spring 23, and a cam 26 fixed to the shaft 25a of the roller thrust motor 25 is in contact with the other end B. Further, a motor 27 is disposed near the gear 22, and a gear 29 fixed to a shaft 27a of the motor 27 is connected to the gear 22.
2 to drive the drive shaft 17. A roller 30 made of sponge material is fixed to the roller shaft 19, and the roller 30 is in pressure contact with the roller 21. Further, a contact cam 31 is fixed to the camshaft 20, and the cam 31 is configured to contact the roller shaft 19 to change the amount of suppression between the shaft 19 and the drive shaft 17. . Further, a gear 32 is fixed to one end of the camshaft 20, and the gear 32 meshes with a gear 35 fixed to a shaft 33a of a cam motor 33. Then, the roller 3
A curl amount detection device 37 is disposed upstream of 0, and the device 36 includes a lever 39 that is swingably supported by a shaft 37 and a sensor 40 that detects the position of one end 39a of the lever 39. It is made up of. Further, the sensor 40 includes a plurality of linearly arranged detection sections 40a...
It is configured to output a detection signal corresponding to the position of the detection section 40a. Furthermore, the sensor 4
The detection signal of 0 is configured to be transmitted to a control unit 41, and the control unit 41 is configured to control the cam motor 33 based on the detection signal of the sensor 40.

Since the present embodiment has the above-described configuration, the image is fixed on the sheet S copied by the copying section (not shown) by the fixing unit 1#3. At this time, the sheet S is curled due to the heat and pressure of the fixing device 3. Then, the sea 1-
S is conveyed from the discharge port 9 to the loading lower of the stacker device 6 by the pair of discharge rollers 5, and is further transferred to the curl amount detection device by the flapper 10! Branch off and be guided to F36. Then, when the seat S comes into contact with the lever 39, the lever 39
It rotates around 7 in the direction of the arrow. As a result, one end 39a of the lever 39 blocks the detection section 40a of the sensor 40 (see ta+ in FIG. 4), and the sensor 40 blocks the detection section 40a of the sensor 40.
A detection signal corresponding to 0a is transmitted to the control unit 41. Furthermore, when the sheet S is highly curled, the lever 39 swings significantly, and the sensor 40 transmits a detection signal corresponding to the position of the detection section 40a blocked by the one end 39a to the control section 41 (see FIG. 4 fbl).

Further, when the curled portion of the sheet +-S passes through the lever 39, the lever 39 returns to the home position, and when the curled portion of the sheet S comes into contact with the lever 39, the sensor 40 is removed by the same operation as described above. A detection signal corresponding to the amount of curl is transmitted to the control section 41. In this manner, the curl amount detection device 36 detects the amount of curl in each portion of the sheet at any time and transmits the detected amount to the control unit. Then, the control section 41
The rotation of the cam motor 33 is controlled based on the detection signal from the curl amount detection device 36 to change the pressing force of the cam 31 against the roller shaft 19. As a result, the pressing force between the rollers 21 and 30, that is, the amount of curl correction of the sheet S changes at each portion of the sheet S at any time. When the sheet S is a full-size sheet, as shown in FIG.
is not operated, and the roller shaft 17 is pressed by the spring 23 to maintain the home position. Also, the sheet is
1 and rollers 30, and the curl that changes in each part is corrected as needed based on the detection signal of the curl amount detection device 136. Further, when the sheet S is a small size sheet 1, as shown in FIG. is activated to move the drive shaft 17 to the right in the axial direction by the cam 26.

As a result, both ends of the sheet S are held between the pair of rollers 21 and 30, and the sheet S is corrected at any time based on the detection signal of the curl amount detection device 36 for curls that change in each portion of the sheet. The curl-corrected sheet S is then discharged to the stacker tray 16 by the discharge roller group 12. In this way, when the sheet S is processed by the sheet post-processing device,
Curling of the sheet can be corrected at each part of the sheet 1- to perform stable processing.

In the above embodiment, the curl straightening device 11 is disposed in the stacker device 6, but the present invention is not limited to this, and the curl straightening device 11 may be disposed in the copying machine main body 2.

In the above embodiment, the curl amount detection device 36 includes a lever 39 that swings in contact with the sheet S, and a sensor 40 that detects the swing amount of the lever 30. However, the curl amount of the sheets 1 and S may be detected by an optical detection means or the like.

(g) As described in detail, according to the present invention, a curl amount detection means for detecting the amount of curl of the sheet in each portion of the sheet;
a curl correcting means disposed downstream of the curl amount detecting means to correct the curl of the sheet; and a correction amount changing means receiving a detection signal from the curl amount detecting means and changing the correction amount of the curl correcting means. and the correction amount changing means is configured to change the correction amount of the curl correction means according to the curl amount of each portion of the sheet detected by the curl amount detection means, so that the curl of the sheet can be reduced. Each portion of the sheet can be corrected at any time to improve sheet alignment.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an image forming apparatus according to the present invention. FIG. 2 is a front view showing the curl amount detection means, curl correction means, and correction amount changing means, and FIG. 3 is a side view showing the curl correction means and the correction amount changing means. In addition, FIG. 4 is a front view showing the operation of the curl amount detection means, and FIG.
The figure is a side view showing the operation of the curl correction means. 1 Image forming device, 21.30 Curl correction means, 20, 31, 32, 33, 33a. 35 - Correction amount changing means, 36 Curl amount detection means, S sheet.

Claims (2)

[Claims] (1) a curl amount detection means for detecting the amount of curl of the sheet in each portion of the sheet; a curl correction means disposed downstream of the curl amount detection means for correcting the curl of the sheet; correction amount changing means that receives the detection signal and changes the correction amount of the curl correction means;
Sheet curl removal characterized in that the correction amount changing means is configured to change the correction amount of the curl correction means according to the curl amount of each portion of the sheet detected by the curl amount detection means. Device. (2) A patent in which the curl correction means is composed of a pair of rollers that press into contact with each other, and at least one of the rollers can move in the axial direction, and at least one roller can move in the vertical direction. A sheet curl removing device according to claim 1.