Riso Kagaku Corporation

Akihiro Yamagata

Masashi Hara

Ryo Terakado

Hirokazu Yabune

A printing system, including a first printing part, a second printing part that is disposed downstream of the first printing part in the conveying direction of a medium, and a conveyance mechanism that conveys the medium The conveyance mechanism includes a passage detection sensor, a conveyor roller, and a resist roller that is disposed downstream in the conveying direction from the passage detection sensor and the conveyor roller, that is butted by the medium, and that conveys the medium slackened due to the butting. The printing system further includes a controller configured to control the conveyor roller so that the slack amount of the subsequent medium is constant based on the conveyance status of the preceding medium and the detection time of the leading edge of the subsequent medium detected by the passage detection sensor.

Printing system

Upon a misfeeding of any of second and subsequent sheets in paper feeding by a paper feeding unit during duplex printing, a controller drives the paper feeding unit to perform a paper feeding retry at one or more of paper feeding timings in a paper feeding schedule for duplex printing. The paper feeding schedule for duplex printing specifies the paper feeding timings by the paper feeding unit and paper refeeding timings by a paper refeeding unit for a case other than the misfeeding of any of the second and subsequent sheets in the paper feeding by the paper feeding unit such that the sheet refed from the paper refeeding unit and the sheet fed from the paper feeding unit are alternately conveyed to a printing unit.

Printer having duplex printing function

Upon continuous feeding of a plurality of sheets and upon detection of a leading end of a sheet by a detection unit before an elapse of a first time after a start of a paper feed roller, a controller performs control such that a paper conveyance speed of the paper feed roller is set lower than a paper conveyance speed of a registration roller, and the paper feed roller is stopped after conveying the sheet having the leading end detected for a specified conveyance distance before a next timing of starting the registration roller.

Paper feeder and printer

A sheet supply device includes registration rollers for feeding a print sheet, a sheet supply roller for feeding a print sheet to the registration rollers, and a controller configured to control the registration rollers and the sheet supply roller. The controller is operable to start first rotation of the sheet supply roller to contact a leading edge of the print sheet to a nip between the registration rollers to form a slack of the print sheet, stop the first rotation after the slack is formed, start rotation of the registration rollers after the first rotation is stopped, start second rotation of the sheet supply roller after the rotation of the registration rollers is started, and keep a speed difference between a feed speed of the registration rollers and a feed speed of the sheet supply rollers until the slack is flattened. According to the device, noises can be reduced.

Sheet supply device

A paper feeder includes a resist roller configured to convey a sheet to an image formation unit, a paper feed roller configured to convey a sheet to the resist roller, and a controller configured to control the paper feed roller such that the paper feed roller first conveys a sheet at a first conveying speed and then conveys the sheet while decelerating from the first conveying speed to a second conveying speed slower than the first conveying speed. The controller sets the first and second conveying speeds in advance to speeds which allow the paper feed roller to convey a single sheet by a predetermined conveying amount in a predetermined driving time period. The controller determines a time point to start a deceleration from the first conveying speed to the second conveying speed to allow a sheet to hit the resist roller at the second conveying speed.

Paper feeder

A sheet supply device includes registration rollers for feeding a print sheet to a print unit, feed rollers for feeding a print sheet to the registration rollers, and a controller for controlling the registration rollers and the feed rollers. The controller starts first rotation of the feed rollers to contact a leading edge of the print sheet to the registration rollers to form a slack with a predetermined slack amount, stops the first rotation after the slack is formed, starts rotation of the registration rollers after the first rotation is stopped to reduce a slack amount of the slack, and starts second rotation of the feed rollers after the rotation of the registration rollers is started so as to make the slack remained until a trailing edge of the print sheet passes through the feed rollers. According to the sheet supply device, noises during feeding print sheets can be reduced.

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Ibaraki, Japan

Akihiro Yamagata