JPH04371432A - Paper feed mechanism - Google Patents

Abstract

PURPOSE:To prevent the suction of any cutform sheet at the time of back line feed with a simplified structure, by moving the carrier of the printer to a specified position to bring a sliding gear into meshing engagement with the sheet-suction gear train, thereby causing sheet suction. CONSTITUTION:An option gear 1 is located on a platen shaft of the printer and is always connected to a slide gear 2 of the sheet feeder. A sheet-discharge drive gear 3 is always connected to the slide gear 2 while a sheet-suction drive gear 4 is connected thereto only when the slide gear 2 has been pushed by a lever 5. When the printer receives a suction command, a carrier 6 of the printer is moved up to an end position of (normal stroke S + added stroke X). The lower end portion of the lever 5 and the slide gear 2 is pushed by the upper end portion of the lever 5. Thus, the slide gear 2 is connected to the drive gear 4 whereby sheet suction becomes ready to be effected. In this way, since the sheet suction operation is controlled in corresponding relation to the carrier 6 position, no cutform sheet is sucked even when back line feed is done during use of document sheet. In addition, the structure is simplified.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed mechanism, and more particularly to a paper feed mechanism for a serial printer.

0002

[Prior Art] In general, a paper feeding mechanism from a sheet feeder in a printer releases only the paper suction drive on the sheet feeder side after feeding the paper sucked in from the sheet feeder to the paper feeding mechanism (platen and pressure roller) of the printer. Must.

FIG. 3 is a partial side view showing an example of a paper feeding mechanism when a sheet feeder is used in a conventional printer, and FIG. 4 is a diagram for explaining the operation of the gears in FIG. 3. The paper feeding mechanism shown in FIG. 3 is a reverse pick type sheet feeder, and the operations from paper feeding to paper ejection will be described with reference to FIGS. 3 and 4.

(1) Initialization: The clutch of pick roller gear D is initialized by forward rotation of platen a. (2) Clutch operation: Engage the clutch of pick roller gear D by rotating reverse → forward → reverse. (3)
Suction operation: Reverse rotation causes paper feeding operation, sucking paper from pick roller d through auxiliary rollers c and h to platen a of the printer. (4) Printer suction operation: During forward rotation, the paper feed pick roller gear D is not driven by the platen a and pressure rollers e and f because the clutch is disengaged. (5) Printing/ejection operation: Ejected by ejection rollers b and g in forward rotation.

[0005] In this way, in the conventional paper feeding mechanism, a one-way clutch or the like is used in the paper suction drive system of the sheet feeder, and the sheet is fed by controlling the printer's paper feed motor (controlling forward and reverse rotation of the platen), which is the drive source. It performs suction drive and release on the feeder side.

[0006]

[Problems to be Solved by the Invention] Since the paper suction drive and release of this conventional sheet feeder are performed by controlling the paper feed motor, when using the sheet feeder with the sheet feeder installed, it is difficult to remove the paper from the sheet feeder. There is a risk that the paper suction operation will occur. Therefore, there were restrictions on reverse line feeds.

[0007]

[Means for Solving the Problems] The paper feeding mechanism of the present invention has a paper ejection system gear train in which the sheet feeder is always in a driving state, and a paper suction system gear train in which the sheet feeder is in a driving state only when a sliding gear is engaged. By moving the carrier of the printer to a specific position, the sliding gear is engaged with the paper suction system gear train to enable paper suction.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the paper feeding mechanism of the present invention;
2(a) is a partial side view in FIG. 1, and FIG. 2(b) is a diagram for explaining the operation.

In FIGS. 1 and 2, an option gear 1 is located on the printer's platen shaft and is always connected to the slide gear 2 of the sheet feeder. The paper ejection system drive gear 3 is always connected to the slide gear 2, and the paper suction system drive gear 4 is connected only when the slide gear 2 is pushed to the left by the lever 5.

Next, the operation of the paper feeding mechanism of this embodiment will be explained. When a paper suction command from the sheet feeder is sent to the printer, the carrier 6 moves to the position of normal stroke S+additional stroke X. Carrier 6 is lever 5
The lower end of the lever 5 is pushed to the right, and the upper end of the lever 5 pushes the slide gear 2 to the left. As a result, the slide gear 2 is connected to the paper suction system drive gear 4, and paper suction becomes possible. When the sucked paper is sent to the paper feed mechanism of the printer,
The carrier 6 is centered (returns to the center position of the normal stroke S), and the slide gear 2 is thereby pushed to the right by the spring, and the connection with the paper suction system drive gear 4 is released.

As described above, in this embodiment, in order to manage the paper suction operation from the sheet feeder at the position of the carrier,
Even if a reverse line feed is performed when a sheet feeder is attached and a form is being used, the form will not be sucked in. Furthermore, since there is no need to use a one-way clutch or the like in the suction drive system, the mechanism and control can be simplified.

0012

As described above, according to the paper feeding mechanism of the present invention, even if a reverse line feed is performed when using a form, no cut form is sucked. Further, since there is no need to use a one-way clutch or the like, it is possible to obtain the effect of simplifying the mechanism and control.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a paper feeding mechanism of the present invention.

2(a) is a partial side view of FIG. 1, and FIG. 2(b) is a diagram for explaining the operation.

FIG. 3 is a partial side view showing an example of a paper feeding mechanism when a sheet feeder is used in a conventional printer.

FIG. 4 is a diagram for explaining the operation in FIG. 3;

[Explanation of symbols]

1 Option gear (printer) 2 Slide gear (sheet feeder) 3 Paper ejection system drive gear (sheet feeder) 4 Paper suction system drive gear (sheet feeder) 5 Lever (printer) 6 Carrier (printer)

Claims (1)

[Claims] Claim 1: A sheet feeder is equipped with a paper ejection system gear train that is always in a driving state and a paper suction system gear train that is in a driving state only when a sliding gear is engaged. A paper feeding mechanism characterized in that by moving the sliding gear, the sliding gear is engaged with the paper suction system gear train, thereby making it possible to suck paper.