US2020165088A1PendingUtilityA1

Image reading apparatus and image forming system

Assignee: MAEYAMA YUICHIROPriority: Nov 27, 2018Filed: Nov 1, 2019Published: May 28, 2020

Est. expiryNov 27, 2038(~12.4 yrs left)· nominal 20-yr term from priority

B65H 5/062B65H 29/20B65H 7/02B65H 2511/512B65H 2511/11B65H 2404/1441G03G 15/5062G03G 15/23G03G 15/6567B41J 13/0045B41J 11/0095H04N 1/00681B65H 29/125B65H 2511/22B65H 2511/224B65H 2404/144B65H 2801/06B65H 7/14

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Claims

Abstract

In at least one embodiment of this disclosure, there is provided an image reading apparatus that includes a reader, an upstream reading conveyance rotator pair, at least one upstream conveyance rotator pair, and an upstream separator. The reader reads a detection target image on a sheet. The upstream reading conveyance rotator pair is disposed upstream from the reader in a sheet conveyance direction to convey the sheet. The upstream conveyance rotator pair is disposed upstream from the upstream reading conveyance rotator pair in the sheet conveyance direction to convey the sheet toward the upstream reading conveyance rotator pair. The upstream separator causes one rotator of the upstream conveyance rotator pair to be contacted against and separated from another rotator of the upstream conveyance rotator pair.

Claims

exact text as granted — not AI-modified

What is claimed is: 
     
         1 . An image reading apparatus comprising:
 a reader configured to read a detection target image on a sheet;   an upstream reading conveyance rotator pair disposed upstream from the reader in a sheet conveyance direction and configured to convey the sheet;   at least one upstream conveyance rotator pair disposed upstream from the upstream reading conveyance rotator pair in the sheet conveyance direction and configured to convey the sheet toward the upstream reading conveyance rotator pair; and   an upstream separator configured to cause one rotator of the upstream conveyance rotator pair to be contacted against and separated from another rotator of the upstream conveyance rotator pair.   
     
     
         2 . The image reading apparatus according to  claim 1 , further comprising:
 a downstream reading conveyance rotator pair disposed downstream from the reader in the sheet conveyance direction and configured to convey the sheet;   at least one downstream conveyance rotator pair disposed downstream from the downstream reading conveyance rotator pair in the sheet conveyance direction and configured to receive the sheet conveyed from the downstream reading conveyance rotator pair to convey the sheet downstream; and   a downstream separator configured to cause one rotator of the downstream conveyance rotator pair to he contacted against and separated from another rotator of the downstream conveyance rotator pair.   
     
     
         3 . The image reading apparatus according to  claim 2 , further comprising a downstream reading conveyance separator configured to cause one rotator of the downstream reading conveyance rotator pair to be contacted against and separated from another rotator of the downstream reading conveyance rotator pair,
 wherein the downstream reading conveyance rotator pair is separated if a distance Lm 1  from a leading end of the sheet to an upstream end of the detection target image in the sheet conveyance direction is longer than a distance L 2  from the reading position in which reading is performed by the reader to the downstream reading conveyance rotator pair.   
     
     
         4 . The image reading apparatus according to  claim 3 , wherein the downstream reading conveyance rotator pair is separated before the leading end of the sheet reaches the downstream reading conveyance rotator pair. 
     
     
         5 . The image reading apparatus according to  claim 3 , wherein the image reading apparatus has a relation of Lmin&gt;(Lm 1 +L 1 ), where L 1  is a distance between the upstream reading conveyance rotator pair and the reading position in which reading is performed by the reader, Lm 1  is the distance Lm 1 , and Lmin is a minimum sheet length passable inside the image reading apparatus. 
     
     
         6 . The image reading apparatus according to  claim 2 , further comprising a plurality of downstream conveyance rotator pairs including the at least one downstream conveyance rotator pair, and
 wherein, out of the plurality of downstream conveyance rotator pairs, a downstream conveyance rotator pair having a shorter distance to the reading position than a maximum length of the sheet to be conveyed is separated.   
     
     
         7 . The image reading apparatus according to  claim 2 , further comprising an upstream reading conveyance separator configured to cause one rotator of the upstream reading conveyance rotator pair to be contacted against and separated from another rotator of the upstream reading conveyance rotator pair,
 wherein the upstream reading conveyance rotator pair is separated if a distance Lm 2  from a trailing end of the sheet to a downstream end of the detection target image in the sheet conveyance direction is longer than a distance L 1  from the upstream reading conveyance rotator pair to the reading position in which reading is performed by the reader.   
     
     
         8 . The image reading apparatus according to  claim 7 , wherein the upstream reading conveyance rotator pair is separated before the detection target image reaches the reading position in which reading is performed by the reader. 
     
     
         9 . The image reading apparatus according to  claim 7 , wherein the image reading apparatus has a relation of Lmin&gt;(Lm 2 +L 2 ), where L 2  is a distance between the reading position in which reading is performed by the reader and the downstream reading conveyance rotator pair, Lm 2  is the distance Lm 2 , and Lmin is a minimum length of the sheet. 
     
     
         10 . The image reading apparatus according to  claim 2 , wherein the image reading apparatus has a relation of L 2 &gt;V×(T 3 +T 4 ), where L 2  is a distance between the downstream reading conveyance rotator pair and the reading position in which reading is performed by the reader, T 3  is a duration of time from when a trailing end of the sheet reaches the reading position to when contact between the downstream conveyance rotator pair begins, T 4  is a duration of time from the beginning of the contact to end of the contact, and V is a sheet conveyance speed. 
     
     
         11 . The image reading apparatus according to  claim 10 , wherein the image reading apparatus has a relation of T 3 +T 4 &gt;0, where −T 3  is a duration of time from when the contact between the downstream conveyance rotator pair begins before a trailing end of the sheet reaches the reading position to when the trailing end of the sheet reaches the reading position after the contact begins. 
     
     
         12 . The image reading apparatus according to  claim 1 , wherein the upstream conveyance rotator pair is separated after a leading end of the sheet reaches the upstream reading conveyance rotator pair and before the leading end of the sheet reaches a reading position in which reading is performed by the reader. 
     
     
         13 . The image reading apparatus according to  claim 1 , wherein the image reading apparatus is configured so that
     L 1&gt; V ×( T 1+ T 2),
   
       where L 1  is a distance between the upstream reading conveyance rotator pair and the reading position in which reading is performed by the reader, T 1  is a duration of time from when a leading end of the sheet P reaches the upstream reading conveyance rotator pair to separation of the upstream conveyance rotator pair begins, T 2  is a duration of time from the beginning of the separation to end of the separation, and V is a conveyance speed of the sheet. 
     
     
         14 . The image reading apparatus according to  claim 1 , further comprising a plurality of upstream conveyance rotator pairs including the at least one upstream conveyance rotator pair, and
 wherein, out of the plurality of upstream conveyance rotator pairs, an upstream conveyance rotator pair having a shorter distance to the reading position than a maximum length of the sheet to be conveyed is separated.   
     
     
         15 . An image forming system comprising:
 the image reading apparatus according to  claim 1 ; and   an image forming apparatus configured to form an image on the sheet.   
     
     
         16 . An image reading apparatus comprising:
 a reader configured to read a detection target image formed on a sheet;   a downstream reading conveyance rotator pair disposed downstream from the reader in a sheet conveyance direction and configured to convey the sheet;   at least one downstream conveyance rotator pair disposed downstream from the downstream reading conveyance rotator pair in the sheet conveyance direction and configured to receive the sheet conveyed from the downstream reading conveyance rotator pair to convey the sheet downstream; and   a downstream separator configured to cause one rotator of the downstream conveyance rotator pair to be contacted against and separated from another rotator of the downstream conveyance rotator pair.   
     
     
         17 . The image reading apparatus according to  claim 16 , further comprising a downstream reading conveyance separator configured to cause one rotator of the downstream reading conveyance rotator pair to be contacted against and separated from another rotator of the downstream reading conveyance rotator pair,
 wherein the downstream reading conveyance rotator pair is separated if a distance Lm 1  from a leading end of the sheet to an upstream end of the detection target image in the sheet conveyance direction is longer than a distance L 2  from the reading position in which reading is performed by the reader to the downstream reading conveyance rotator pair.   
     
     
         18 . The image reading apparatus according to  claim 17 , wherein the downstream reading conveyance rotator pair is separated before the leading end of the sheet reaches the downstream reading conveyance rotator pair. 
     
     
         19 . The image reading apparatus according to  claim 17 , further comprising a plurality of downstream conveyance rotator pairs including the at least one downstream conveyance rotator pair, and
 wherein, out of the plurality of downstream conveyance rotator pairs, a downstream conveyance rotator pair having a shorter distance to the reading position than a maximum length of the sheet to be conveyed is separated.   
     
     
         20 . An image forming system comprising:
 the image reading apparatus according to  claim 16 ; and   an image forming apparatus configured to form an image on the sheet.

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