PUNCHING DEVICE, SHEET PROCESSING DEVICE AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide a punching device which reduces the number of components and makes a punching member movable in a punching direction while rotating the punching member, and to provide a sheet processing device and an image forming apparatus including the punching device.SOLUTION: A punching device 3 sets a transmission part to be driven of a punching member such as a punching pin 310 as a spiral groove part 309. Further, a driving transmission part for transmitting a driving force to the transmission part to be driven of the punching member formed on a sliding member such as a slide arm 322 which performs sliding movement in parallel to a sheet surface is set as a contact part such as inclined straight line projection parts 322b which is brought into contact with the spiral groove part 309. Therein, an inclination angle for a sheet surface of a spiral part is set to be less than an inclination angle α for a sheet surface of the contact part and the punching member is moved in the orthogonal direction for the sheet surface while rotating the punching member on the basis of a relationship of the contact part and the spiral part in accordance with a sliding movement of the sliding member. 【課題】部品点数を削減して、穿孔部材を回転させながら穿孔方向へ移動可能にする穿孔装置、これを備えた用紙処理装置及び画像形成装置を提供する。【解決手段】穿孔装置３は、穿孔ピン３１０などの穿孔部材の被駆動伝達部を螺旋状溝部３０９とした。また、シート面と平行にスライド移動するスライドアーム３２２などのスライド部材に形成された穿孔部材の被駆動伝達部に駆動力を伝達する駆動伝達部を、螺旋状溝部３０９に接触する斜め直線凸部３２２ｂなどの接触部とした。そして、螺旋部のシート面に対する傾斜角度βを、接触部のシート面に対する傾斜角度α未満とし、スライド部材のスライド移動に伴う接触部と螺旋部との係わり合いにより穿孔部材を回転させながら、穿孔部材をシート面に対して直交方向に移動させる。【選択図】図９