Punching unit

Abstract

The invention discloses a punching unit. The invention provides a rotary-type punching unit that solves a problem of a prior art rotary-type punching unit that its punching torque is highly peaked in beginning and ending punching, thus disabling to punch a heavy paper or the like and degrading the quality level of punch holes. A blade surface (13a) of a punch (13) of the invention is formed as an inclined surface inclined with respect to the outer peripheral surface of a punch shaft or of a die shaft such that a leading edge (A) thereof is higher than a trailing edge (C) with an inclination angle Theat within a range of 5 DEG to 15 DEG (preferably 10 DEG ). A die surface (22a) of the die is formed into a surface of a circular arc centering on a rotational axis (O) of the shafts. Thereby, the peaks of the punching torque are reduced and the quality level of the punch hole is kept high.

Description

technical field [0001] The present invention relates to a perforating unit attached to image forming devices such as copiers and printers. The perforating unit is used to perforate recording paper, in particular to a rotary perforating unit. Background technique [0002] Conventionally, there has been a rotary piercing unit that rotates a punch shaft and a die shaft that are arranged in parallel with each other and has a plurality of punches and dies, so that the punches of the punch shaft and the dies of the die shaft are engaged to punch the paper. perforate on. [0003] The above-mentioned rotary perforating unit is generally as Figure 8 As shown in (b), the front end faces (cutter face and stamping face) of the punch 13' and the die 22' are constituted by a plane perpendicular to the radial direction line r passing through the rotation axis O of the shaft. 13'a and the front edge of the stamping surface 22'a start to engage (start to perforate), and the engagement of t...

AI Technical Summary

Problems solved by technology

[0006] The device described in the above-mentioned Patent Document 1 reduces the driving torque of the punch and the die by reducing the peak value of the piercing torque, and reduces the rigidity of the punch and the die shaft, so that the drive mechanism can be miniaturized, but the surface of the punch blade The shape is complex, and it is difficult to sufficiently reduce the piercing torque, especially the torque at the end of cutting, due to the influence of the clearance when engaging with the die

[0007] Recently, large-scale and high-performance copiers for light printing and bookbinding have appeared. The copiers sometimes use colored paper made of coated hard paper and thick paper for covers and back covers. If the power supply capacity or cost of the copier is considered Considering the angle, the improvement of the motor and rigidity of the perforating unit is limited, so it is difficult to perforate the above-mentioned colored paper and thick paper with the above-mentioned perforating unit

[0008] In addition, the gap between the punch and the die should be large in the above-mentioned piercing unit in which the shape of the head surface of the punch is convex, and as a result, there are problems such as a decrease in sharpness, hairiness at the incision, and a decrease in the quality of the hole.

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