JPS61162066A - Variable power copying machine - Google Patents

Abstract

PURPOSE:To prevent a copied picture from the generation of picture notch due to the intrusion of a picture into a leading erase part at the time of variable power copying by setting up the variable power to a value slightly smaller than a normally fixed power determined from the ratio of original size to transfer paper size. CONSTITUTION:Although the normally fixed power determined by the ratio of the original size to the transfer paper size is ordinally used, lens arrangement or the like at the time of power variation is set up in the copying machine so that an original picture does not enter into at least the leading erase area. When it is defined that the leading erase width is (a), the half length of transfer paper 42 is (b), a set power (m), and a normally fixed power is m', m<={(b-a)/ b}m' is set. Since the leading erase width (a) is fixed in common to all size of transfer paper 42, the picture notch is not generated in the transfer paper 42 of all size at the time of variable power copying by setting up respective power values on the basis of the transfer paper 42 having the minimum size (b).

Description

Detailed Description of the Invention Technical Field The present invention has an erase function for the tip of an image area,
The present invention also relates to a variable magnification copying machine in which the image reference is a lens optical axis reference.

BACKGROUND TECHNOLOGY In general, in this type of copying machine, in order to improve the separation of the transfer paper by the separation claw of the fixing roller, leading edge erase is performed to prevent an image from being formed on the leading edge of the transfer paper. There is. Here, looking at the magnification of magnification, B4
The size is set based on the ratio between the standard original size and the transfer paper size, such as size→A4 size and B5 size→A5 size. Considering such a magnification and the above-mentioned edge erase, there are many cases in which the image corresponding to the edge erased portion of the original image is not copied. Such image defects may also occur due to variations in the leading edge of the transfer paper or original, or in the left and right resists.

OBJECTS The present invention has been made in view of the above points, and an object of the present invention is to provide a variable-magnification copying machine capable of copying without causing image loss due to edge erase.

In order to achieve the above object, the present invention provides a variable magnification copying machine which has an erase function for the leading edge of an image area and in which one image reference is a lens optical axis reference.

It is characterized in that the variable magnification is set to be slightly smaller than the normal fixed magnification determined by the ratio of the X document size and the transfer paper size.

Hereinafter, one embodiment of the present invention will be described based on the drawings. First, FIG. 1 schematically shows an optical system having a variable magnification function with the image reference being the lens optical axis reference. An original 3 set on a contact glass 1 and pressed by a pressure plate 2 is exposed by an exposure lamp 4. illuminated. The exposure amplifier 4 serves as a first scanner 7 together with a reflection plate 5 and a first mirror 6 to scan the surface of the document in the direction of the arrow. The reflected light from the original 3 is transmitted to the first mirror 6, the second mirror 8, and the third mirror 9.
, is imaged onto the photosensitive drum 12 via the lens 10 and the fourth mirror 11. Here, the second and third mirrors 8
, 9 is a second scanner 13, which is set to move in the same direction as the first scanner 7 at 1/2 the speed. Further, as will be described later, the second scanner 13 and lens 10 are moved along the optical axis direction in accordance with the magnification when changing the magnification.

Next, a variable magnification drive mechanism for the lens 10 and the second scanner 13 is shown in FIGS. 2 to 4. First, lens 10
is held by the lens block 14 and is movable in the Y-axis direction (optical axis direction) along guide shafts 15 and 16. The rotation of the lens drive motor 17 causes the timing belt 18, timing pulley 19. It is set to be transmitted to the variable power cam pulley 22 and the mirror shift cam 23 via the worm 2o and the worm wheel 21. This variable power cam pulley 22 has a pulley 24
A lens wire 25 is wound around the lens wire 25, and when the variable power cam pulley 22 rotates based on the motor 17, the lens wire 25 is fixed to the solder lens block 14 (therefore,
The lens 10) is moved and displaced in the Y-axis direction.

26 is a lens stopper, and 27 is a stopper solenoid. On the other hand, when the mirror shift cam 23 rotates, the bracket 28 that is in contact with the cam 23 slides. This bracket 28 is provided with a pulley 29, and as shown in FIG. 4, a mirror shift wire 30 having one end fixed is wound around the cylinder 31 from this pulley 29 and fixed.

Further, a wire 33 partially fixed to the cylinder 31 by a clamp 32 is passed between a plurality of fixed pulleys 34 and a second scanner pulley 35. With this mechanism as shown in FIG. 4, when the bracket 28 slides, the second scanner pulley 35 also moves and the second scanner 13 is displaced. With such a mechanism, lens arrangement and optical path length correction are performed in accordance with the variable magnification.

FIG. 5 shows a part of the operation panel 36, including the copy button 37. In addition to the numeric keypad 38 and the clear key 39, a plurality of magnification selection keys 40 are provided so that the user can select a variable magnification from the original size and the transfer paper size. Note that 41 is a display section that indicates the selection state.

Although such a configuration has been adopted in the past, in this embodiment, the setting of the magnification of the variable power is different. That is, conventionally, the normal fixed magnification is determined by the paper size ratio between the original size and the transfer paper size.

In this embodiment, the lens arrangement etc. at the time of changing the magnification are set so that the magnification is slightly smaller than such a fixed magnification, and the document image is prevented from entering at least the tip erase area.1For example, As shown in FIG. 6, if the leading edge erase width is a, and the half length of the transfer paper 42 is b, the set magnification in this embodiment is m, and the normal fixed magnification is m', then m≦((b -a)/b) m', where the leading edge erase a is common and constant for all sizes of transfer paper 42, so for each magnification setting, b is the minimum, that is, the minimum size. Transfer paper 42
If you set each magnification based on.

A good copy including all original images can be obtained without image loss occurring at the time of variable-magnification copying for transfer paper 42 of all sizes.

Regarding the magnification such as 1.1 magnification, it is likely that a fixed magnification based on the ratio of the original size and the transfer paper size is required, so the magnification such as 1.1 magnification may remain a fixed magnification.

Effects In the present invention, as mentioned above, the variable magnification is set to be slightly smaller than the normal fixed magnification determined from the ratio of the original size and the transfer paper size. There will be no defects,
It is possible to obtain good copies.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic side view of the optical system, Fig. 2 is a plan view of the variable power drive mechanism, Fig. 3 is a perspective view of a part thereof, and Fig. 4. 5 is a perspective view schematically showing the mirror shift system, FIG. 5 is a plan view of the operation panel, and FIG. 6 is a plan view of the transfer paper. Applicant Ricoh Co., Ltd. -JJ Figure UZ diagram

Claims (1)

[Claims] In a variable-magnification copying machine that has an erase function for the leading edge of the image area and uses the lens optical axis as the image reference, the variable magnification is set higher than the normal fixed magnification determined by the ratio of the original size and the transfer paper size. A variable magnification copying machine characterized by a slightly smaller setting.