Riso Kagaku Corporation

Riso Kagagu Corporation

Yukihiro Maeda

Masashi Hara

Kenji Oshima

Masatoshi Fujimoto

Tomohiko Shimoda

Ryo Terakado

Masakazu Kawano

Hirohide Hashimoto

A controller performs a positioning operation by driving an elevator motor before starting a paper feed operation using a paper feed roller unit. While the controller performs the paper feed operation using the paper feed roller unit after an upper limit sensor is brought into an on-state by the positioning operation, when the upper limit sensor is brought into an off-state, the controller performs a paper feed position following operation by driving the elevator motor to raise a paper feed tray until the upper limit sensor is brought into the on-state. The controller controls the elevator motor with setting a current limit in the positioning operation such that a current flowing to the elevator motor does not exceed a predetermined current limit value and controls the elevator motor without the current limit in the paper feed position following operation.

Paper feed device

A printer is operable for image formation onto a sheet of a sheet width Lp, with a sheet spacing Lg and a printing transfer speed Vg, a constant speed transferrer makes sheet transfer at the printing transfer speed Vg from a register via the printer to a speed change position, a variable speed transferrer makes sheet transfer from the speed change position to the register, and a transfer controller controls sheet transfer speeds, the variable speed transferrer having sections for sheet transfer, including deceleration and acceleration sections for sheet reversal at the sheet reversing path, and a constant speed section for transfer at a constant transfer speed Vr, the transfer controller determining a circulating sheet number N, executing a calculation of transfer speed Vr employing sheet width Lp, sheet spacing Lg, printing transfer speed Vg, and accelerations, to enable sheet transfer for circulation within a time interval of N&#xd7;(Lp+Lg)/Vg.

Duplex printing apparatus with variable speed section

A conveyance control mechanism for a printer including an image forming unit forming an image on a sheet being conveyed on a conveyance route, includes a curl detector configured to detect a curl of the sheet conveyed on the conveyance route, in an upstream of the image forming unit on the conveyance route. The conveyance route controller may drive and stop the conveyance route differently depending on whether the curl detector detects a curl at either a front end or at a position other than the front end. When the curl detector detects a curl of the sheet, an image forming route where the image forming unit performs an image formation may be separated and retreated from the conveyance route and the sheet being conveyed may be discharged onto the retreated image forming route.

Transfer control mechanism for printer and transfer control method

A printing apparatus comprises: a first paper discharge roller unitand a second paper discharge roller unitwhich are configured to transport a print sheet to a discharge port; a upper transportation roller unitconfigured to transport the print sheet to the first paper discharge roller unit; a drive control unitconfigured to determine a transportation speed; an upper side paper discharge drive unitconfigured to drive both the paper discharge roller units at the determined transportation speed after starting transportation of the print sheet until the print sheet leaves the upper transportation roller unit, and drive both the paper discharge roller units at a discharge speed which is determined independently from the transportation speed until the print sheet leaves the second paper discharge roller unit

Printing apparatus having discharge speed control

An image forming apparatus including: a print-job controller configured to receive a print job and control a printing operation based on the received print job; an ink-ejection driver configured to output a driving signal on the basis of the print job; an ink ejector configured to eject ink onto a paper sheet on the basis of the driving signal outputted by the ink-ejection driver; and an ink-temperature measuring unit configured to measure an ink temperature. When the ink temperature measured by the ink-temperature measuring unit is equal to or higher than a first reference temperature, the ink-ejection driver outputs a driving signal of a first voltage. When the ink temperature measured by the ink-temperature measuring unit is lower than the first reference temperature and is equal to or higher than a second reference temperature that is lower than the first reference temperature, the print-job controller performs the printing operation as long as predetermined conditions are satisfied for suppressing lowering of print quality possibly caused by ink ejection based on a driving signal of a second voltage that is higher than the first voltage and the ink-ejection driver outputs the driving signal of the second voltage while the printing operation is being performed.

Inkjet image-forming apparatus and method for printing

A hybrid printing apparatus and related control method have a first print section composed of a plurality of printing machines located in parallel to one another, and a second print section composed of one printing machine and connected to the first print section, via a print medium transfer section having a transfer passage composed of discrete passage components which include change-over rollers to change over start/stop operations in transfer of print media and medium detection sensors to detect leading edges of the print media discharged from the respective printing machines of the first print section , respectively. A control section controls timings at which the change-over rollers are changed over, so as to sequentially transfer the printing media from the first section to the second print section in response to detection signals from the medium detection sensors

Hybrid printing apparatus and related control method

A stencil printer includes a printing drum which is rotated bearing a stencil wound around the printing drum, a pair of paper feed rollers which are rotated in contact with each other to supply a printing paper to the printing drum, and a press roller which is rotated in contact with the printing drum to convey the printing paper supplied to the printing drum with the printing paper pressed against the stencil on the printing drum. A paper feed roller driver drives the paper feed rollers, and a paper feed roller controller controls the paper feed roller driver to rotate the paper feed rollers at a peripheral speed higher than that of the printing drum at least from the time the leading end of the printing paper reaches the printing drum to the time the trailing end of the printing paper passes the paper feed rollers.

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Ibaraki-ken, Japan

Yukihiro Maeda