Sheet processing apparatus and sheet processing method

Abstract

A sheet processing apparatus includes a puncher disposed to make a hole in a sheet to be conveyed, a moving mechanism configured to move the puncher in the orthogonal direction to a conveyance path of the sheet, a sensor to detect a forward edge and a rear edge of the sheet conveyed into the puncher, and a controller configured to control the conveyance of the sheet and an operation of the puncher. The controller decelerates the sheet from a first conveying speed to a second conveying speed after the sensor detects the forward edge of the sheet, and stops the conveying of the sheet after the sensor detects the rear edge of the sheet, and executes a punching to the sheet.

1 . A sheet processing apparatus comprising:
 a puncher disposed to make a hole in a sheet to be conveyed;   a moving mechanism configured to move the puncher in an orthogonal direction to a conveyance path of the sheet;   a sensor to detect a forward edge and a rear edge of the sheet conveyed into the puncher; and   a controller configured to control the conveyance of the sheet and an operation of the puncher, the controller decelerates the sheet from a first conveying speed to a second conveying speed after the sensor detects the forward edge of the sheet, and stops the conveying of the sheet after the sensor detects the rear edge of the sheet, and executes a punching to the sheet.   
     
     
         2 . The sheet processing apparatus according to  claim 1 , further comprising:
 a first detector to detect a skew of the conveyed sheet; and   a skew correction unit configured to carry out skew correction of the conveyed sheet;   wherein the first detector detects an amount of skew at the forward edge of the sheet when the sheet is being conveyed at the first conveying speed, and detects an amount of skew at the rear edge of the sheet when the sheet is being conveyed at the second conveying speed.   
     
     
         3 . The sheet processing apparatus according to  claim 1 , wherein the controller changes timing of decelerating the conveying speed of the sheet from the first conveying speed to the second conveying speed in accordance with a size of the conveyed sheet. 
     
     
         4 . The sheet processing apparatus according to  claim 3 , wherein the controller sets the timing of decelerating the conveying speed of the sheet from the first conveying speed to the second conveying speed closely to timing when the sensor detects the rear edge of the sheet. 
     
     
         5 . The sheet processing apparatus according to  claim 3 , wherein a pulse-driven stepping motor is used for conveying the sheet, and
 the controller controls a period from when the sensor detects the forward edge of the sheet until the conveying speed is decelerated to the second conveying speed, by a number of pulses set for each size of the sheet.   
     
     
         6 . The sheet processing apparatus according to  claim 1 , the sensor being arranged at a central part of the sheet conveying path. 
     
     
         7 . The sheet processing apparatus according to  claim 1 , further comprising:
 a second detector to detect an edge in a direction of width of the sheet conveyed to the puncher;   wherein the controller controls the moving mechanism in accordance with the result of detection of the second detector, and moves the puncher in the orthogonal direction to the conveyance path align with the result of detection by the second detector.   
     
     
         8 . A sheet processing method comprising:
 arranging a puncher orthogonally to a conveying path of a sheet;   conveying the sheet along the conveying path;   moving the puncher in the orthogonal direction to the conveyance path of the sheet and positioning the puncher;   detecting a forward edge and a rear edge of the sheet conveyed into the puncher, by a sensor;   decelerating the sheet from a first conveying speed to a second conveying speed after the sensor detects the forward edge of the sheet;   stopping the conveying of the sheet after the sensor detects the rear edge of the sheet; and   executing a punching to the sheet by the puncher when the sheet is stopped.   
     
     
         9 . The sheet processing method according to  claim 8 , further comprising:
 providing a first detector to detect a skew of the conveyed sheet and a skew correction unit configured to carry out skew correction of the conveyed sheet;   wherein an amount of skew at the forward edge of the sheet is detected when the sheet is being conveyed at the first conveying speed, and an amount of skew at the rear edge of the sheet is detected when the sheet is being conveyed at the second conveying speed.   
     
     
         10 . The sheet processing method according to  claim 8 , wherein timing of decelerating the conveying speed of the sheet from the first conveying speed to the second conveying speed is changed in accordance with a size of the conveyed sheet. 
     
     
         11 . The sheet processing method according to  claim 10 , wherein the timing of decelerating the conveying speed of the sheet from the first conveying speed to the second conveying speed is set closely to tithing when the sensor detects the rear edge of the sheet. 
     
     
         12 . The sheet processing method according to  claim 10 , further comprising:
 using a pulse-driven stepping motor for conveying the sheet along the conveying path;   wherein a period from when the sensor detects the forward edge of the sheet until the conveying speed is decelerated to the second conveying speed is controlled by a number of pulses set for each size of the sheet.   
     
     
         13 . The sheet processing method according to  claim 8 ,
 detecting an edge in a direction of width of the sheet conveyed to the puncher by a second detector, and moving the puncher in the orthogonal direction to the conveyance path align with the position in the direction of width of the conveyed sheet in accordance with the result of detection by the second detector.   
     
     
         14 . An image forming apparatus comprising:
 an image forming unit including a printer configured to form an image on a sheet;   a conveying section conveying the sheet outputted from the image forming unit, along a conveying path;   a puncher disposed to make a hole in a sheet conveyed by the conveying section;   a moving mechanism configured to move the puncher in an orthogonal direction to a conveyance path of the sheet;   a sensor to detect a forward edge and a rear edge of the sheet conveyed into the puncher; and   a controller configured to control the conveyance of the sheet and an operation of the puncher, the controller decelerates the sheet from a first conveying speed to a second conveying speed after the sensor detects the forward edge of the sheet, and stops the conveying of the sheet after the sensor detects the rear edge of the sheet, and executes a punching to the sheet.   
     
     
         15 . The image forming apparatus according to  claim 14 , further comprising:
 a first detector to detect a skew of the conveyed sheet; and   a skew correction unit configured to carry out skew correction of the conveyed sheet;   wherein the first detector detects an amount of skew at the forward edge of the sheet when the sheet is being conveyed at the first conveying speed, and detects an amount of skew at the rear edge of the sheet when the sheet is being conveyed at the second conveying speed.   
     
     
         16 . The image forming apparatus according to  claim 14 , wherein the controller changes timing of decelerating the conveying speed of the sheet from the first conveying speed to the second conveying speed in accordance with a sheet size designated on an operation panel. 
     
     
         17 . The image forming apparatus according to  claim 14 ,
 the conveying section including a pulse-driven stepping motor for conveying the sheet along the conveying path;   wherein the controller controls a period from when the sensor detects the forward edge of the sheet until the conveying speed is decelerated to the second conveying speed, by a number of pulses set for each size of the sheet.