Ricoh Company, Ltd.

Nichiro Kogyo Co., Ltd.

Shuichi Kikuchi

Masami Itoh

Tetsuya Hoshino

Katsumi Oda

An engageable pawl member is provided so as to be swingable about a supporting shaft so that a pawl tip is movable along a moving path for a strapping band. The engageable pawl member is pulled forwardly in a swinging direction by a helical tension spring to push the pawl tip against the strapping band. The engageable pawl member shifts forwardly, following the movement of the strapping band in a feeding direction, and the strapping band is sandwiched and held between the engageable paw member and a holding guide. Then, the engageable pawl member follows the movement of the strapping band in a direction to pull back, and the engageable pawl member shifts backwardly so that the pawl tip moves in a direction out of the moving path for the strapping band.

Operable sealing mechanism for a strapping band

A lens system includes a master lens system and a conversion lens system. The master lens system has a first lens, a second lens, a third lens, and a fourth lens, which are sequentially arranged from an object side of the lens system to an image side thereof, and has a first diaphragm which is arranged between the third lens and the fourth lens. The first lens is a positive meniscus lens having a convex surface toward the object side. The second lens is a negative lens. The third lens is a positive lens. The fourth lens is a negative meniscus lens having a concave surface toward the object side. The conversion lens system is arranged in such a manner that the conversion lens system can be freely inserted and removed between the third lens and the fourth lens of the master lens system. When the conversion lens system is inserted and removed between the third lens and the fourth lens, relative positions of the respective first, second, third and fourth lenses are fixed, and a focal length of the lens system becomes shorter than a focal length of the master lens system.

Lens system with master lens system and conversion lens

A zoom lens having a super wide angle has a first lens group having positive refracting power and arranged on an object side of the zoom lens; a second lens group having negative refracting power and arranged on an image side of the zoom lens; and a converter lens having positive refracting power and detachably attached between the first and second lens groups. A focal length of the zoom lens is changed by changing a distance between the first and second lens groups. The distance between the first and second lens groups is set to be wide on a wide angle side in a zooming region and narrow on a telescopic side in the zooming region. The focal length of the zoom lens at the super wide angle is set to be shorter than that at a wide angle end in the zooming region by mounting the converter lens on the wide angle side. In accordance with this structure, the super wide angle at a focal length shorter than that at a normal wide angle can be realized by adding the converter lens to the zoom lens composed of the first positive lens group and the second negative lens group without substantially increasing an entire length of the zoom lens.

Zoom lens having super wide angle

A compact zoom lens has first to fourth lens groups sequentially arranged from an object side. The first, second and fourth lens groups respectively have negative, positive and negative focal lengths. When a zooming operation is performed from a wide angle end to a telescopic end, a distance between the first and second lens groups is decreased, a distance between the second and third lens groups is increased, and a distance between the third and fourth lens groups is decreased. Focal lengths f.sub.1 and f.sub.2 of the first and second lens groups, focal lengths f.sub.2,3,4W and f.sub.2,3,4T of a combined lens system of the second, third and fourth lens groups at the wide angle end and the telescopic end, a focal length f.sub.3,4T of a combined lens system of the third and fourth lens groups at the telescopic end, focal lengths f.sub.W and f.sub.T of an entire lens system at the wide angle end and the telescopic end satisfy the following conditions where symbol .sqroot.[ ] means a square root of a value within bracket [ ].

Compact zoom lens

In a zoom lens having a high variable magnification, first and second lens groups and respectively having negative and positive focal lengths are sequentially arranged from an object side of the zoom lens to an image side thereof. A combined focal length of an entire lens system is charged by changing a distance between the first and second lens groups while the position of an image surface is constantly held. The zoom lens is constructed such that the second lens group is constructed by front and rear lens groups respectively having positive and negative focal lengths.

Zoom lens having high variable magnification

A compact zoom lens has a first lens group having a negative focal length f.sub.1 ; a second lens group having a positive focal length f.sub.2 ; and a third lens gorup having a negative focal length f.sub.3. The first, second and third lens groups are sequentially arranged from an object side of the zoom lens to an image side thereof. The first to third lens groups are moved on the object side while the mutual distances between the first, second and third lens groups are changed to perform a zooming operation from a wide angle side to a telescopic side. The third lens group is constructed by positive, negative and positive lenses sequentially arranged from the object side to the image side such that the negative and positive lenses respectively constituting the second and third lenses are joined to each other. The focal lengths f.sub.1, f.sub.2, f.sub.3 and a focal length f.sub.w of an entire lens system at a wide angle end of the zoom lens satisfy the following conditions.

A zoom lens comprises first to third lens groups sequentially arranged from an object side toward an image side and respectively having negative, positive and negative focal distances; a first zoom region for performing a zooming operation from a wide angle side to a telescopic side by moving at least the first lens group onto the image side; and a second zoom region for performing the zooming operation from the wide angle side to the telescopic side by moving all the lens groups onto the object side further from the telescopic end of the first zoom region while the distances between the lens groups are changed with respect to each other; the focal distances of the respective lens groups and the focal distance of the entire lens system at the wide angle end satisfying predetermined inequality conditions. A focusing method in the above zoom lens comprises the steps of performing a focusing operation by moving the second lens group on an optical axis in the first zoom region; and performing the focusing operation by moving the first lens group on the optical axis in the second zoom region.

Zoom lens and focusing method

A zoom finder of a real image type comprises an objective lens composed of a first lens group having a positive refracting power, a second lens group having a negative refracting power, and a third lens group having a positive refracting power, the objective lens having a positive refracting power as a whole; an eyepiece composed of a fourth lens group having a positive refracting power; a device for forming a real image by the objective lens between the third and fourth lens groups and observing this real image through the eyepiece; and a device for increasing the magnification of the finder by moving the second lens group from an object side to an eyepiece side. The change is diopter of the finder caused by a zooming operation in the movement of the second lens group is corrected by displacing the first and third lens groups.

Zoom finder of real image type

A zoom lens comprises a front lens group having a positive focal length and a rear lens group having a negative focal length, with the distance between the front and rear lens groups being variable for varying the magnification of the zoom lens. The front lens group comprises a first front lens group having a negative focal length and a second front lens group having a positive focal length, the first and second front lens groups being successively arranged in the order specified from an object side. The first front lens group comprises, in the order named from the object side, at least a positive lens and a negative lens. The second front lens group comprises at least one negative lens and at least two positive lenses. The rear lens group comprises, in the order specified from the object side, a positive lens, a negative lens, a negative lens, and a positive lens. The distance between the first and second front lens groups varies during zooming movement of the zoom lens.

Zoom lens

A zoom lens comprises successively in order from an object toward an image, a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having positive refracting power, and a fifth lens unit having negative refracting power. When the zoom lens is zoomed from a wide angle setting to a telephoto setting, the first lens group, the third lens group, the fourth lens group, and the fifth lens unit are moved toward the object, whereas the second lens group is moved toward the image. The zoom lens meets the following conditions:

Growing community of inventors

Yokohama, Japan

Shuichi Kikuchi