Offset printing machine comprising improved control mechanism
AssigneeRicoh Company, Ltd.
InventorsTamaki Kaneko, Tugio Okuzawa
Life of this patent
Estimating the term…
Abstract
A mechanism actuates a sheet feed means after a predetermined length of time after a control lever is moved to a print position, thereby allowing sufficient ink to be transferred to a transfer roller such that the first sheet printed has the same density as subsequent sheets. The mechanism comprises a ratchet and a pawl, the pawl being reciprocatingly driven in synchronism with the transfer roller and advancing the ratchet from a reset position to a position in which it engages with a sheet feed control linkage to activate the sheet feed means in a predetermined number of reciprocations corresponding to the predetermined length of time.
Claims8
In a printing machine including a printing means, a sheet feed means for feeding sheets to the printing means for printing and a control member movable between a neutral position for de-activating the printing means and sheet feed means and a print position for activating the printing means, an improvement for activating the sheet feed means after a predetermined length of time after the control member is moved from the neutral position to the print position, said improvement comprising the combination of:
- a ratchet formed with an actuating member, the ratchet being rotatable between a reset position in which the actuating member is disengaged from the sheet feed means thereby de-activating the sheet feed means and an actuating position in which the actuating member engages with the sheet feed means thereby activating the sheet feed means;
- a drive pawl arranged to be reciprocatingly driven to engage with and advance the ratchet from the reset position to the actuating position in a predetermined number of reciprocations thereof corresponding to the predetermined length of time;
- drive means for reciprocatingly driving the drive pawl;
- a holding pawl for engaging with and thereby preventing rotation of the ratchet from the actuating position to the reset position;
- reset means actuated by the control member to move the drive pawl and the holding pawl out of engagement with the ratchet thereby allowing the ratchet to move to the reset position when the control member is moved from the neutral position to an intermediate position between the neutral position and the print position, the reset means moving the drive pawl and the holding pawl into engagement with the ratchet when the control member is moved from the intermediate position to the print position;
- and
- latch means actuated by the control member for disconnecting the drive means from the drive pawl when the control member is in the neutral position and connecting the drive means to the drive pawl when the control member is moved from the neutral position to the print position, the latch means continuing to disconnect the drive means from the drive pawl when the control member is in the intermediate position.
Dependencies are inferred from the claim text.