JP2021107272A5 - - Google Patents

Description

The image forming apparatus of the present invention includes sheet storage means for storing sheets, transport means for transporting the sheets stored in the sheet storage means, and the length of the sheets stored in the sheet storage means in the transport direction. sheet setting means for setting a certain first length; multi-feed detection means for detecting whether or not two or more sheets are overlapped and conveyed by the conveying means; sheet detecting means arranged upstream of the detecting means for detecting the sheet conveyed by the conveying means; sheet measuring means for detecting a second length, and when the second length is longer than the first length, the overlapping of the sheets is detected by the double feeding detecting means based on the difference between the second length and the first length. and control means for determining a position at which to start and causing the multi-feeding detection means to detect the overlap of the sheets from the determined position.

The sheets accommodated in the paper feed cassette 55 are fed one by one from the paper feed cassette 55 to the conveying path by separating paper feed units 56 and 57 such as pickup rollers. A transport sensor 62 is provided on the transport path. The transport sensor 62 is used to detect the sheet measurement length (second length ), which is the length of the sheet being transported in the transport direction. A sheet transported from the paper feed cassette 55 to the transport path is transported to the paper feed vertical path. Vertical path rollers 58 are provided in the paper feed vertical path. Vertical pass rollers 58 convey the sheet to horizontal pass 30 .

The control unit 200 includes a CPU (Central Processing Unit) 301 , a RAM (Random Access Memory) 302 and a ROM (Read Only Memory) 303 . The CPU 301 controls the overall operation of the image forming apparatus 101 by executing computer programs stored in the ROM 303 . A RAM 302 provides a work area for the CPU 301 to perform various types of processing. A PDL (Page Description Language) control unit 304 and an internal interface (I/F) unit 305 are connected to the CPU 301 . A PDL control unit 304 is a processing circuit for processing, storing, and image processing of print data. An internal I/F unit 305 is a communication interface for communicating with the printer control unit 201 .

A device control unit 314 is an electric circuit including an input/output port for controlling each component provided inside the image forming apparatus 101 . The device control unit 314 is connected to the double feed detection sensor 60, the transport sensors 61, 62, 63, and the like. Internal I/F section 315 is a communication interface for communicating with control section 200 . The internal I/F section 315 and the internal I/F section 305 transmit and receive image signals and timing signals. The CPUs 311 and 301 communicate with each other via internal I/F units 315 and 305 and cooperate to perform various processes.

Claims (11)

a sheet containing means for containing a sheet;
a conveying means for conveying the sheet accommodated in the sheet accommodating means;
sheet setting means for setting a first length, which is the length of the sheet accommodated in the sheet accommodation means in the conveying direction;
multi-feed detection means for detecting whether or not two or more sheets are overlapped and conveyed by the conveying means;
a sheet detection means disposed at a position upstream of the multi-feeding detection means in the conveying direction and configured to detect the sheet conveyed by the conveying means;
sheet measuring means for detecting a second length, which is the length of the sheet being conveyed by the conveying means in the conveying direction, based on the detection result of the sheet detecting means;
If the second length is longer than the first length, then based on the difference , the position at which detection of the overlap of the sheets is to be started is determined by the multi-feed detection means, and the multi-feed detection means determines and a control means for detecting the overlapping of the sheets from the position where
Sheet conveying device. When the second length is longer than the first length, the control means starts detecting the overlap of the sheets at a position shifted forward by a predetermined distance from the trailing edge of the sheet in the conveying direction. characterized by setting a position,
The sheet conveying device according to claim 1. When the second length is shorter than the first length, the control means determines not to detect the overlapping of the sheets by the double feeding detection means,
The sheet conveying device according to claim 1 or 2. The control means sets a position at which detection of overlapping of the sheets is started at a leading end of the sheet in the conveying direction when a difference between the first length and the second length is equal to or less than a predetermined threshold. characterized by
The sheet conveying device according to any one of claims 1 to 3. The control means causes the multi-feed detection means to start detection of overlapping of the sheets based on detection of the sheets by the sheet detection means,
If the sheet detecting means has not set a position to start detection of overlapping of the sheets when the sheet detecting means detects the sheet, the control means moves forward a predetermined distance from the trailing edge of the sheet in the conveying direction. characterized by setting a position to start detecting the overlapping of the sheets at the shifted position,
The sheet conveying device according to any one of claims 1 to 4. The double feeding detection means includes a transmission means for transmitting ultrasonic waves and a reception means for receiving the ultrasonic waves, and the ultrasonic waves transmitted from the transmission means pass through the sheet and are received by the reception means. The transmitting means and the receiving means are arranged so that the overlapping of the sheets is determined by the intensity of the ultrasonic wave received by the receiving means,
The sheet conveying device according to any one of claims 1 to 5 . The control means causes the double-feeding detection means to detect whether or not the sheets overlap and are conveyed within a range of a predetermined distance from the set position where detection of overlapping of the sheets is started. characterized by
The sheet conveying device according to any one of claims 1-6 . The sheet setting means comprises operation means for inputting the first length by a user's operation,
The sheet conveying device according to any one of claims 1-7 . The paths along which the sheet is transported by the transport means include a first pass and a second pass different from the first pass,
wherein the control means conveys the sheet to the second pass by the conveying means when the double feeding detecting means detects that two or more sheets are overlapped and conveyed,
The sheet conveying device according to any one of claims 1-7 . If the second length is longer than the first length by a predetermined threshold value or more when the double feeding detection unit does not detect that two or more sheets are overlapped and conveyed, the control unit characterized in that the sheet is conveyed to the second pass by the conveying means,
The sheet conveying device according to claim 9 . A sheet conveying device according to any one of claims 1 to 10 ;
and image forming means for forming an image on the sheet conveyed by the sheet conveying device,
Image forming device.

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