JP3687719B2 - Tooth jump prevention device in a gear train mechanism of a printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tooth jump prevention device for a train wheel mechanism applied to a printer or the like.
[0002]
[Prior art]
For example, in a printer, a mechanism is adopted in which a support shaft is fixed in a cantilever shape to a frame made of sheet metal from the viewpoint of layout or assembly, and an intermediate transmission gear that transmits driving force is supported here. ing.
[0003]
However, when such a support mechanism is adopted, as shown in FIG. 3, the intermediate transmission gear c provided on the cantilever shaft b on the side frame a is transferred from the drive gear d to the counterclockwise direction in the drawing. The intermediate transmission gear c that meshes with the pulley shaft drive gear f of the tractor e is displaced in the direction of the arrow in the figure while bending the shaft b or the side frame a in response to the load resistance of the paper feed. There is a disadvantage that tooth jumping may occur between the pulley shaft driving gear f or the driving gear d.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of such problems, and an object of the present invention is to provide a new tooth jump prevention mechanism capable of reliably suppressing tooth jump between gears without increasing the number of parts. There is.
[0005]
[Means for Solving the Problems]
That is, in order to achieve such a problem, the present invention provides a side frame constituting a printer main body, an intermediate gear provided on a support shaft fixed to the side frame in a cantilever shape, and the intermediate gear from one end. And a paper guide plate formed by bending a shaft support piece so as to extend outward, and having a hook-shaped bearing portion recessed at the tip of the shaft support piece. In the process of fixing to the support shaft, the hook-shaped bearing of the shaft support piece engages with the free end of the support shaft to support the free end of the support shaft, thereby reducing the displacement of the support shaft without increasing the number of parts. This is to suppress the tooth jump of the intermediate gear .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Therefore, examples of the present invention will be described below.
1 and 2 show an embodiment of the present invention applied to a printer.
[0007]
One end of the support shaft 2 is fixed to the side frame of the printer main body denoted by reference numeral 1 in the figure in a cantilever shape, and meshes with one transmission gear 9 in the driving force transmission wheel train. A driving force transmission idler 8 for transmitting the driving force to the pulley shaft driving gear 13 of the tractor unit 10 is rotatably mounted, and the locking step 3 provided on the side frame 1 is provided with rigidity. A paper guide plate 4 bent to have an L-shaped cross section is suspended over the left and right side frames 1 and assembled and fixed so as to be integrated as a whole.
[0008]
Engagement holes 5 are provided at both ends of the paper guide plate 4 for engaging the locking pieces 12 provided at the lower end of the support base 11 constituting the tractor unit 10 and fixing the support base 11. A shaft support piece 6 is bent upward at a portion extending from one end of the paper guide plate 4 toward the outside of the idler 8, and the free end of the support shaft 2 is formed at the tip of the shaft support piece 6. And a hook-shaped bearing 7 that holds the support shaft 2 so as not to be separated from the shaft of the transmission gear 9 or the pulley shaft drive gear 13 of the tractor unit 10 is recessed. The bending of the support shaft 2 and the bending of the side frame 1 that occur when a feed load is applied are suppressed so that no tooth jump occurs between the idler 8 and the gears 9 and 13. Yes.
[0009]
The tooth jump prevention mechanism configured as described above is bent at one end in the process of fixing the paper guide plate 4 so as to be inserted into the locking step 3 provided on the left and right side frames 1 from above. Since the hook-shaped bearing 7 of the shaft support piece 6 can be engaged with and supported by the free end of the support shaft 2, even when a paper feeding load is applied to the idler 8 via the pulley shaft drive gear 13, the support is supported. The shaft support piece 6 that is freely engaged with the shaft 2 ensures displacement of the support shaft 2 in the direction of the arrow in the figure by the rigidity acting in the surface direction of the paper guide plate 4 and the shaft support piece 6 bent in an L shape. Therefore, the occurrence of tooth jump between the idler 8 and the transmission gear 9 or the pulley shaft drive gear 17 can be suppressed in advance.
[Brief description of the drawings]
FIG. 1 is a perspective view of an apparatus showing an embodiment of the present invention.
FIG. 2 is an exploded perspective view of the apparatus.
FIG. 3 is a diagram showing an example of a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Side frame 4 Paper guide board 6 Shaft support piece 7 Hook-shaped bearing 8 Idler 9 Transmission gear 10 Tractor 13 Pulley shaft drive gear

Claims (1)

An intermediate gear provided on a support shaft fixed in a cantilever shape to a side frame constituting the printer main body, and a shaft support piece formed by bending so as to extend outward from one end of the intermediate gear. It consists of a paper guide plate with a hook-shaped bearing part recessed at the tip of the bearing piece,
In the process of fixing the paper guide plate to the side frame, a hook-shaped bearing of the shaft support piece engages with the free end of the support shaft to support the free end of the support shaft . Tooth jump prevention device in a train wheel mechanism.

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