Medium conveying apparatus, image forming apparatus, and medium conveying system

Abstract

A medium conveying apparatus includes a conveying unit including two rotating members for conveying a medium therebetween, a driving unit configured to drive a rotation of at least one of the rotating members, a parameter calculating unit configured to calculate a parameter of the driving unit, and a medium detecting unit configured to detect the medium conveyed by the rotating members by comparing the parameter calculated by the parameter calculating unit when the medium is conveyed by the rotating members and a reference parameter calculated by the parameter calculating unit when the medium is not conveyed by the rotating members.

What is claimed is: 
     
         1 . A medium conveying apparatus comprising:
 a conveying unit including two rotating members for conveying a medium therebetween;   a driving unit configured to drive a rotation of at least one of the rotating members;   a parameter calculating unit configured to calculate a parameter of the driving unit; and   a medium detecting unit configured to detect the medium conveyed by the rotating members by comparing the parameter calculated by the parameter calculating unit when the medium is conveyed by the rotating members and a reference parameter calculated by the parameter calculating unit when the medium is not conveyed by the rotating members.   
     
     
         2 . The medium conveying apparatus as claimed in  claim 1 ,
 wherein the parameter calculated by the parameter calculating unit includes a torque of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference torque.   
     
     
         3 . The medium conveying apparatus as claimed in  claim 2 , further comprising:
 a time estimating unit configured to estimate when the medium passes an area between the rotating members; and   a conveying status detecting unit configured to determine a conveying status of the medium;   wherein the conveying status detecting unit is configured to determine that the conveying status is a failure when the medium detecting unit does not detect the medium at the time estimated by the time estimating unit or when the medium detecting unit detects the medium after the time estimated by the time estimating unit.   
     
     
         4 . The medium conveying apparatus as claimed in  claim 2 , further comprising:
 an upstream conveying unit configured to convey the medium to the conveying unit; and   a downstream conveying unit configured to receive the medium conveyed from the conveying unit;   wherein in a case of conveying the medium from the upstream conveying unit to the conveying unit, the driving unit is configured to drive the rotation of at least one of the rotating members, so that a medium conveying speed of the conveying unit is greater than or equal to a medium conveying speed of the upstream conveying unit,   wherein in a case of conveying the medium from the conveying unit to the downstream conveying unit, the driving unit is configured to drive the rotation of at least one of the rotating members, so that the medium conveying speed of the conveying unit is less than or equal to a medium conveying speed of the downstream conveying unit.   
     
     
         5 . The medium conveying apparatus as claimed in  claim 1 ,
 wherein the parameter calculated by the parameter calculating unit includes a rotation speed of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference speed.   
     
     
         6 . An image forming apparatus comprising:
 a medium conveying apparatus including
 a conveying unit including two rotating members for conveying a medium therebetween; 
 a driving unit configured to drive a rotation of at least one of the rotating members; 
 a parameter calculating unit configured to calculate a parameter of the driving unit; and 
 a medium detecting unit configured to detect the medium conveyed by the rotating members by comparing the parameter calculated by the torque calculating unit when the medium is conveyed by the rotating members and a reference parameter calculated by the calculating unit when the medium is not conveyed by the rotating members. 
   
     
     
         7 . The image forming apparatus as claimed in  claim 6 ,
 wherein the parameter calculated by the parameter calculating unit includes a torque of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference torque.   
     
     
         8 . The image forming apparatus as claimed in  claim 6 ,
 wherein the parameter calculated by the parameter calculating unit includes a rotation speed of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference speed.   
     
     
         9 . A medium conveying system comprising:
 a medium conveying apparatus including a conveying unit having two rotating members for conveying a medium therebetween;   a server apparatus connected to the medium conveying apparatus;   a driving unit configured to drive a rotation of at least one of the rotating members;   a parameter calculating unit configured to calculate a parameter of the driving unit; and   a medium detecting unit configured to detect the medium conveyed by the rotating members by comparing the parameter calculated by the parameter calculating unit when the medium is conveyed by the rotating members and a reference parameter calculated by the parameter calculating unit when the medium is not conveyed by the rotating members.   
     
     
         10 . The medium conveying system as claimed in  claim 9 ,
 wherein the parameter calculated by the parameter calculating unit includes a torque of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference torque.   
     
     
         11 . The medium conveying system as claimed in  claim 9 ,
 wherein the parameter calculated by the parameter calculating unit includes a rotation speed of the driving unit,   wherein the reference parameter calculated by the parameter calculating unit includes a reference speed.