SHEET CONVEYANCE DEVICE CAPABLE OF DETECTING SHAPE OF SHEET, IMAGE FORMING APPARATUS, SHEET SHAPE DETECTING METHOD

• US 20180334345A1
• Filed: 05/16/2018
• Published: 11/22/2018
• Est. Priority Date: 05/22/2017
• Status: Active Application

• Current Assignee: KYOCERA Document Solutions, Inc. (Kyocera Corporation)
• Original Assignee: KYOCERA Document Solutions, Inc. (Kyocera Corporation)
• Inventors: Mashimo, Takayuki, Mutsuo, Toshiaki
• Granted Patent: US 10,273,103 B2
• Time in Patent Office: Days
• CPC Class Codes: B41J 11/008 Controlling printhead for accurately positioning print image on printing material, e.g. with the intention to control the width of margins
• CPC Class Codes: B41J 11/0095 Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end
• CPC Class Codes: B41J 13/0009 control of the transport of the copy material
• CPC Class Codes: B65H 2404/14 Roller pairs
• CPC Class Codes: B65H 2408/10 for handling sheet(s)
• CPC Class Codes: B65H 2511/10 Size; Dimensions
• CPC Class Codes: B65H 2513/10 Speed
• CPC Class Codes: B65H 2513/50 Timing
• CPC Class Codes: B65H 2553/40 using optical, e.g. photographic, elements
• CPC Class Codes: B65H 2557/10 for signal transmission
• CPC Class Codes: B65H 2601/26 Damages to handling machine
• CPC Class Codes: B65H 2801/15 Digital printing machines
• CPC Class Codes: B65H 3/32 by elements, e.g. fingers, plates, rollers, inserted or traversed between articles to be separated and remainder of the pile such elements acting only as supplementary devices to assist separation or prevent double feed B65H3/50
• CPC Class Codes: B65H 5/062 between rollers or balls
• CPC Class Codes: B65H 7/14 by photoelectric feelers or detectors
• CPC Class Codes: B65H 7/20 Controlling associated apparatus
• CPC Class Codes: B65H 9/002 changing orientation of sheet by only controlling movement of the forwarding means, i.e. without the use of stop or register wall
• CPC Class Codes: G03G 15/5029 by measuring the copy material characteristics, e.g. weight, thickness
• CPC Class Codes: G03G 15/6529 Transporting G03G15/6555 takes precedence
• CPC Class Codes: G03G 2215/00746 of sheet velocity

Abstract

A sheet conveyance device includes a shape detecting portion, and a switch control portion. The shape detecting portion detects a shape of a sheet at a detection position between a first conveyance member and a second conveyance member. The switch control portion, when a front end of the sheet has passed a arrangement position at which the first conveyance member is arranged, switches an detection interval at which the shape of the sheet is detected by the shape detecting portion, to a first interval that corresponds to a rotation speed of the first conveyance member, and when a rear end of the sheet has passed the arrangement position, switches the detection interval to a second interval that corresponds to the rotation speed of the second conveyance member.

Claims

1. A sheet conveyance device comprising:

a first conveyance member provided on an upstream side of an image forming position in a conveyance path along which a sheet is conveyed, the first conveyance member being rotationally driven in a driving cycle in which the first conveyance member enters a driven state where the first conveyance member is driven while decelerated in a stepped manner, and then the first conveyance member is decelerated to a stopped state;

a second conveyance member configured to convey the sheet at the image forming position by being rotationally driven to rotate at a specific speed that is a lowest speed in the driven state;

a shape detecting portion including a light emitting portion and a light receiving portion, the light emitting portion being configured to emit light toward a detection position located between the first conveyance member and the second conveyance member in the conveyance path, the light extending in a width direction of the sheet perpendicular to the conveyance path, the light receiving portion being configured to receive the light that has been emitted from the light emitting portion and reflected on the sheet passing the detection position, and output a detection signal corresponding to an amount of received light, the shape detecting portion being configured to detect a shape of the sheet based on the detection signal;

a first speed detecting portion configured to detect a rotation speed of the first conveyance member;

a second speed detecting portion configured to detect a rotation speed of the second conveyance member;

a determination processing portion configured to determine whether or not a front end of the sheet that is being conveyed has passed an arrangement position at which the first conveyance member is arranged, and determine whether or not a rear end of the sheet that is being conveyed has passed the arrangement position;

a switch control portion configured to, when the determination processing portion determines that the front end of the sheet has passed the arrangement position, switch an output interval at which the detection signal is output from the light receiving portion, to a first interval that corresponds to the rotation speed detected by the first speed detecting portion, and when the determination processing portion determines that the rear end of the sheet has passed the arrangement position, switch the output interval to a second interval that corresponds to the rotation speed detected by the second speed detecting portion.

2. The sheet conveyance device according to claim 1, further comprising:

a sheet detecting portion configured to detect whether or not the sheet is present at the arrangement position, wherein

the determination processing portion determines whether or not the front end of the sheet has passed the arrangement position and determines whether or not the rear end of the sheet has passed the arrangement position, based on the rotation speed detected by the first speed detecting portion and a detection result of the sheet detecting portion.

3. The sheet conveyance device according to claim 2, wherein

the light receiving portion outputs the detection signal in response to an input of a predetermined electric signal,

the first speed detecting portion outputs the electric signal in a cycle corresponding to a reciprocal of a rotation speed of the first conveyance member,

the second speed detecting portion outputs the electric signal in a cycle corresponding to a reciprocal of a rotation speed of the second conveyance member,

the sheet conveyance device further comprises:

a measurement processing portion configured to measure an output cycle of the electric signal input from the second speed detecting portion;

a signal output portion configured to output the electric signal each time the output cycle measured by the measurement processing portion elapses, and

when the determination processing portion determines that the front end of the sheet has passed the arrangement position, the switch control portion switches an output source of the electric signal that is input to the light receiving portion, to the first speed detecting portion, and when the determination processing portion determines that the rear end of the sheet has passed the arrangement position, the switch control portion switches the output source of the electric signal to the signal output portion.

4. The sheet conveyance device according to claim 3, wherein

after the determination processing portion determines that the rear end of the sheet has passed the arrangement position, the switch control portion switches the output source of the electric signal to the signal output portion simultaneously when the electric signal that is output from the first speed detecting portion for a first time after the determination processing portion determines that the rear end of the sheet has passed the arrangement position is input to the light receiving portion, and resets a time measured by the signal output portion.

5. The sheet conveyance device according to claim 2, wherein

the light receiving portion outputs the detection signal in response to an input of a predetermined electric signal,

the first speed detecting portion outputs the electric signal in a cycle corresponding to a reciprocal of a rotation speed of the first conveyance member,

the second speed detecting portion outputs the electric signal in a cycle corresponding to a reciprocal of a rotation speed of the second conveyance member,

the sheet conveyance device further comprises:

a storage portion having a plurality of storage areas;

a measurement processing portion configured to measure an output cycle of the electric signal input from the second speed detecting portion, and each time it measures one output cycle, the measurement processing portion stores the output cycle in one of the storage areas so that output cycles are stored in sequence in the storage areas;

a signal output portion configured to output the electric signal each time a specific period corresponding to a moving average of the output cycle stored in each of the storage areas elapses, and

when the determination processing portion determines that the front end of the sheet has passed the arrangement position, the switch control portion switches an output source of the electric signal that is input to the light receiving portion, to the first speed detecting portion, and when the determination processing portion determines that the rear end of the sheet has passed the arrangement position, the switch control portion switches the output source of the electric signal to the signal output portion.

6. The sheet conveyance device according to claim 3, further comprising:

when the determination processing portion determines that the front end of the sheet has passed the arrangement position, the switch control portion switches the output source of the electric signal to the first speed detecting portion, and restricts the electric signal that is output from the first speed detecting portion for a first time after the switch control portion switches the output source to the first speed detecting portion, from being input to the light receiving portion.

7. The sheet conveyance device according to claim 1, further comprising:

a setting processing portion configured to set a reference value that is used by the shape detecting portion to detect the shape of the sheet, based on the detection signal output from the light receiving portion while the first conveyance member is in the stopped state, wherein

the shape detecting portion detects the shape of the sheet by using the reference value set by the setting processing portion.

8. An image forming apparatus comprising:

the sheet conveyance device according to claim 1; and

an image forming portion configured to form an image on a sheet at the image forming position.

9. The image forming apparatus according to claim 8, further comprising:

a restriction processing portion configured to restrict the image forming portion from forming an image beyond the sheet, based on the shape of the sheet detected by the shape detecting portion.

10. The image forming apparatus according to claim 8, wherein

the image forming portion forms the image on the sheet by an inkjet system.

11. A sheet shape detecting method executed on a sheet conveyance device which includes a first conveyance member, a second conveyance member, a shape detecting portion, a first speed detecting portion, and a second speed detecting portion, the first conveyance member being provided on an upstream side of an image forming position in a conveyance path along which a sheet is conveyed, the first conveyance member being rotationally driven in a driving cycle in which the first conveyance member enters a driven state where the first conveyance member is driven while decelerated in a stepped manner, and then the first conveyance member is decelerated to a stopped state, the second conveyance member being configured to convey the sheet at the image forming position by being rotationally driven to rotate at a specific speed that is a lowest speed in the driven state, the shape detecting portion including a light emitting portion and a light receiving portion, the light emitting portion being configured to emit light toward a detection position located between the first conveyance member and the second conveyance member in the conveyance path, the light extending in a width direction of the sheet perpendicular to the conveyance path, the light receiving portion being configured to receive the light that has been emitted from the light emitting portion and reflected on the sheet passing the detection position, and output a detection signal corresponding to an amount of received light, the shape detecting portion being configured to detect a shape of the sheet based on the detection signal, the first speed detecting portion being configured to detect a rotation speed of the first conveyance member, the second speed detecting portion being configured to detect a rotation speed of the second conveyance member, the sheet shape detecting method comprising:

determining whether or not a front end of the sheet that is being conveyed has passed an arrangement position at which the first conveyance member is arranged, and determining whether or not a rear end of the sheet that is being conveyed has passed the arrangement position; and

when it is determined that the front end of the sheet has passed the arrangement position, switching an output interval at which the detection signal is output from the light receiving portion, to a first interval that corresponds to the rotation speed detected by the first speed detecting portion, and when it is determined that the rear end of the sheet has passed the arrangement position, switching the output interval to a second interval that corresponds to the rotation speed detected by the second speed detecting portion.