JPS58174964A - Variable power copying machine - Google Patents

Abstract

PURPOSE:To enable the matching of the forward end of an original and a copying material in the stage of variable power copying as well by exactly the same control as the control in unmagnification copying, by rotating a photosensitive drum at all times at a constant peripheral speed and starting conveying the copying material in the stage when the projection of the image at the forward end of the original to the drum is started. CONSTITUTION:The central position in the projection part on a photosensitive drum 4 is designated as a point B, the forward end position of a copying material 39 placed in a cassette 37 as a point D and the transfer position where the sensible image of the drum 4 is transferred to the material 39 as a point C. If the conveyance of the material 39 is started simultaneously at the point of the time when the projection of the image at the forward end of the original to the point B is started where the distance LBC between B and C and the distance LDC between D and C are equal, the forward ends of the original image and the copying material coincide surely in the transer position C because the peripheral speed of the drum 4 is equal to the conveying speed of the copying material. The conveying speed of the original is changed according to the variable power copying and since the drum side rotates always at a constant peripheral speed, the forward ends are matched at the same control as the control in the stage of unmagnification copying.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying device that forms a copied image by projecting an original image onto a photoreceptor in the form of a slit. The present invention relates to a copying apparatus that forms a copy image using a machine.

2. Description of the Related Art Conventionally, there is a copying apparatus that moves or conveys a document (hereinafter simply referred to as conveyance) and projects an image of the document onto a photoreceptor in the form of a slit. When the above-mentioned apparatus has a magnification ratio of 28 or higher, generally the copying material and the photoreceptor are always transported at the same speed, while the original is transported at a speed corresponding to each magnification. method has been adopted. A copying apparatus to which the J method described above is applied operates only the means for changing the projection magnification of the optical system such as a lens and the conveyance speed of the original conveyance means in accordance with the selection of the magnification, This has the advantage that the mechanisms and conditions for transporting paper and copy materials are not subject to change. On the other hand, for example, in a copying apparatus that conveys a sheet-like original by a drive + GK such as a roller, and projects an image of the original onto a drum-like photoreceptor to obtain a copy ldIIgl, #11 on the photoreceptor The leading edge of the microscope image and the leading edge of the copying material are completely synchronized so that they coincide at the transfer position so that [[] can be transferred to a predetermined position on the copying material transported to the transfer position (hereinafter referred to as (simply referred to as tip alignment) is required. The time point at which the image leakage reaches the transfer position is a certain period of time after the point at which the leading edge of the document is projected onto the photoreceptor, regardless of the magnification. However, since the document conveyance speed is changed in accordance with the selected magnification, the time point at which the image at the tip of the lid M is projected onto the photoreceptor differs depending on the selected magnification. In such a case, K, which achieves edge alignment, detects the document being conveyed and
Either change the timing of the start of conveyance of the copy material using the delay means corresponding to each magnification, or arrange a plurality of document detection members at positions corresponding to each magnification, and selectively VC the document detection members according to the set magnification. A method is conceivable in which the copy material transport start timing is determined based on signals from these document detection members.

However, the above method requires a large number of delay means and detection members in a copying apparatus capable of making multiple types of variable-magnification copies, making the apparatus complicated and making adjustment difficult. do not have.

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned inconveniences, and to make it possible to perform edge alignment without complicating the apparatus no matter how many types of variable size copying are performed.

The present invention also includes a document conveying means for conveying the document at a speed corresponding to a selected magnification, and an optical means for projecting the original at the selected magnification onto a photoreceptor that moves at the same speed regardless of the magnification. In the O1 variable magnification copying device, which has a transfer means for transferring an original image formed on the photoreceptor to a copy material moving at the same speed as the photoreceptor, a Kuryo Tachibana detection means is installed in the original conveyance path. , a rotating member that rotates at a speed corresponding to a selected magnification in conjunction with the document conveying means, and means for detecting the amount of rotation of this (b) rotating member, and the document detecting means detects the document. The above rotating member was selected from the time of death 1
6. A variable-magnification copying device characterized in that it detects that it has rotated by the same amount of rotation regardless of the rotation rate, and starts conveying the copying material that has been kept waiting with the tip position set in advance at a predetermined position to a transfer position. be.

As the document detecting means, a micro switch, a switch using ultrasonic waves, or a switch combining a light source and a ψ optical element may be used. Also, in the present invention,
The photoreceptor is drum-shaped or web-shaped, and moves together with a copying material such as plain paper at a constant speed regardless of changes in magnification. The (moving) speed of the photoreceptor means the circumferential speed due to rotation when the photoreceptor is drum-shaped, and the moving speed when the photoreceptor is web-shaped. Further, the document is in the form of a sheet, and the present invention is particularly effective for documents that are conveyed while being held between rollers or belts with a slit portion for projecting the document image onto a photoreceptor. Further, the present invention can also be applied to a movable document table on which eight sheet-like or three-dimensional documents are placed and moved through the slit portion.

Embodiments of the present invention will be explained below in detail with reference to the drawings. It has a 14th light section 1 with a fixed original document table and a 2nd jlII light section 2 having an original conveying means dedicated to sheet documents. The present invention is applied to the second exposure section side of the exposure section 1.2, and variable magnification copying can be performed only on sheet originals. The photoreceptor is formed into a drum shape, and the photoreceptor drum 4 rotates in the direction of the arrow. A photoreceptor having six insulating layers is used. Next, the operation of the above device will be briefly explained.

When using the first exposure section 1, place the original on the original glass plate 5 of the exposure section and press the copy start button (not shown), the photosensitive drum 4 will rotate in the direction of the arrow. start. Next, the lamp 6 for illuminating the original of the optical system and the first movable mirror 7 move in the direction of the arrow at the same speed as the circumferential speed of the drum 4. Then, in synchronization with the scissor first mirror 7, 812
The movable mirror 8 moves in the same direction at half the speed of the mirror 70 to scan the document. The original image is guided to the projection section 11 of the drum 4 via the first mirror, the second mirror 7 and 8, the in-lens mirror 9 which is fixed and includes an aperture and a mirror inside, and the rotatable third mirror 10. It will be destroyed. In addition, 2
The first and second mirrors 7 and 8, which have reached the dot-dashed line position, reverse their moving directions and return to the starting position.

Next, the case where the second exposure section 2 is used will be described. In this case, the original 11 is placed on the original guide 12 where originals can be placed one on top of the other.
13 and press the copy start button (not shown), the feed roller 14 and reversing roller 15 work to
The original s13 is sent out one by one from the guide 12. The sent out document 13 is transferred to the glass plate 18 by a pair of conveyance rollers 16 and further by a pair of conveyance rollers 43 and 44.
The sheet passes through a slit section having a slit portion, and is further conveyed onto a sheet discharge tray 21 by rollers 19 and 20. In addition, the above 2nd I
When using the l light s2, the third mirror lO is located at the position indicated by the two-dot chain line, and the reflected image of the document illuminated through the mirror 18 is configured in a movable mode to change the optical cliff length. Through a mirror unit 23, which is a mirror unit 23, and a lens 24, which is also movable in order to change the magnification of the original image,
The projection section 11 of the photoreceptor is reached.

On the other hand, members and means for forming an image are arranged around the upper photosensitive drum 4, and in the figure, 25 is a @1 corona discharger, and 26 is an AC corona discharger, which is applied to the photosensitive drum. The charge eliminating action and the image projection are performed simultaneously, and 27 turns on the lamp for full exposure. An electrostatic image corresponding to the original image is formed on the surface of the photosensitive drum 4 by each of these members 25 to 27. Thereafter, the electrostatic image on the photosensitive drum is
It is converted from c and reaches the transfer section.

In the transfer section, copying material is conveyed in accordance with the visible image on the photosensitive drum, and the copying material tightly adhered to the photosensitive drum 4 in the transfer section receives the electric field of the transfer discharger 29 and is transferred to the drum 4.
The upper image is transferred. The copy material that has been transferred is separated from the drum 4 by the separating means 3o, and is delivered via the fixing means 31 to the transport roller 32 onto the small paper discharge tray 33. On the other hand, after the transfer process is completed, the photosensitive drum 4 is uniformly irradiated by the rung 34, and is further exposed to the cleaning roller 3.
5 and cleaning blade 36, residual dust and image agent on the surface are removed, and the image is ready for the next step.

In the above figure, the cassette for storing 37/38 Fi copy materials can also store copy materials 39 of different sizes. Further, 4o and 41 are delivery rollers for sending out the copy material, and the copy material 39 that is sent out by the sales roller 41 is synchronized by the register roller 42.
The photosensitive drum 4 is transported to a transfer section.

Here, when performing variable magnification copying of /-tohara Kusunoki using the upper IT: 2nd second city light, if the copying magnification ratio is 1 = 1 / n, the conveyance speed of the original is set to is Vo, then the conveyance speed Vn of the document during variable-magnification copying is Vo: Vn=l
Make it a two-n relationship. Further, the mirror unit 23τ moves and the lens 24 moves to the position indicated by the two-dot chain line, thereby forming an optical path for variable magnification projection.

Next, the relationship between the projection of the original image from the second exposure section 2, the projected image on the photoreceptor, and the synchronization of conveying the copying material with respect to the image on the photoreceptor will be described. Note that the numbers in FIG. 2 and the following figures are the same as the corresponding members in the apparatus 1 shown in FIG. be.

In FIG. 2, the center position of the projection part on the photosensitive drum 4 is designated as point B, the tip position of the copying material 39 loaded in the cassette 37 is designated as point D, and the visible image on the drum 4 is located on the copying material 39. The center position of the transfer position to be transferred to is set as the 0 point.

And, the length along the circumferential direction on the elongated surface of the drum marked F,
Let LBO be the distance between point B and point C, and let LDO be the distance between point C and the leading edge position of the copy material, which is the length along the conveyance path between the cassette 37 and the drum 4.

, Figure 82 shows the case where the configuration is LBO=LDO,
If the conveyance of the copy material 39 is started at the same time that the leading edge image of the document starts to be projected onto the point B, the document will be moved at the transfer position C because the circumferential speed of the drum 4 and the conveyance speed of the copy material are equal as described above. The image and the leading edge of the copy material can be reliably aligned. In addition, although the conveyance speed of the document changes with variable-magnification copying, since the drum side always rotates at a constant circumferential speed, it is necessary to start conveying the copy material at the moment when the leading edge image of the document starts to be projected onto the drum 4. The edge alignment can be reliably performed using the same control as when copying at the same size.

FIG. 3 shows a case where the LBO (LDO) configuration is used in FIG.
Transport it to A and keep it on standby. Please note that the copy material is
Examples of methods for conveying at point position 1 include (distance between point 11 and point 8 - LDE) using a timer to drive the roller 40, (b1 point E with a micro switch, ultrasonic element,
The position of the copy material being conveyed may be detected by a detection means such as light and a light receiving element, and the roller 40 may be stopped. Here, set it to Li5o2LEO. By aligning the leading edge of the copying material with the point E and keeping it on standby in a good condition as described above, when the leading edge image of the document starts to be projected at the projection position H as in the configuration shown in FIG. If the conveyance of the copy material 39 is restarted from position E, it is possible to perfectly align the leading edges for full-size and other variable-magnification copies.

FIG. 4 shows a case where the configuration in FIG. 2 is such that I, Bo > LDO. In this case, the copy material 39 is moved along a path corresponding to the difference between LBO and LoD for the time required for the copy material 39 to be conveyed at a constant speed from the time when the end of the document 5 starts to be projected at 13 points. Delay the start of transport using a timer, etc. This makes it possible to align the leading edge of the 1i copy material at the transfer position C point.

As mentioned above, the distance between the projection position of the original image and the transfer position,
Even if the distance between the feeding position of the copy material and the transfer position is different, it is possible to move the photoconductor side and the copy material I41I at the same speed and align the leading edges. By determining the start time of projection onto the body,
Regardless of whether the magnification is the same or variable, the edges can always be aligned perfectly.

Therefore, the means tic for determining the projection start time will be explained below using an example.

FIG. 5 shows the second light transmitting section of the apparatus shown in FIG.

In the figure, the width a is the slit width for document illumination;
is the center position of the ridge width a. The sheet-like original is conveyed in the direction of arrow T at a speed appropriate for the selected magnification. In the above configuration, when the leading edge of the IM bucket passes point A, it indicates the point in time when the leading edge image of the document is projected to point B in FIGS. 2 to 4. In other words, the leading edge of the document passes point A. The time of passing is detected, and the detected point is used to command the conveyance of the above-mentioned copying material whose leading edge is pre-arranged at the same position for any magnification! It's okay.

By the way, as a method for detecting the sound of a copying material passing through point A, a microswitch is provided at the point A and the presence of the document is detected based on the thickness of the document when it passes, or a light source and a light receiving element are provided at point A.1. A possible method is to detect the presence of a document by blocking the light from the light source when the document passes through the document. However, since the point Art is the foggy light position of the document, if these position detection means are provided in the slit section, these detection means will be projected onto the photoreceptor together with the document image. The present invention also improves the above points. In the present invention, when the leading edge of the document passes the document detection means, the time required for the rotating member described below to rotate by a predetermined amount is added to determine the point at which the document starts to be projected onto the photoreceptor. There is.

In FIG. 5, there is one document leading edge detection member I provided along the document conveyance path, and a rotating member that rotates in conjunction with the document conveyance means at the same speed as the document detection means. 43/44Fi11 in the figure! A pair of original paper sheet feeding rollers forming a part of the document conveyance means, 45 is a pulse generation plate, and the wire plate 45 is fixed to the above-mentioned conveyance roller 43, avoiding the document conveyance path, and has the same rotational angular velocity as the roller 43. Linked with. Therefore, the rows 243 and 44 rotate at a speed corresponding to the selected magnification in order to convey the document at a speed corresponding to the selected magnification, and accordingly, the pulse generator plate 45 also rotates at a speed corresponding to the selected magnification. Rotate. N1 holes are provided at equal intervals on the outer periphery of the pulse generating plate 45. A fixed member 46 extending across the holes is a pulse signal detecting member. Here, if the distance between the upper i self-detecting section ■ installed at the upstream position of the slit section Sj4 i and the center A of the slit section with respect to the transport direction TK is d, then the leading edge of the document is located at the detecting section I.
After reaching , in order to transport this original by d, the original transport roller 43 only needs to rotate its outer periphery by an amount corresponding to the distance d, that is, by an angle α (as shown in the figure), regardless of its rotational speed. . The angle at which the pulse generation plate 45 rotates at this time is also α, and the number of pulses detected by the pulse detection member 46 during this time is also N2−, -N I X 2. Therefore, the relationship is always constant regardless of the document conveyance speed. From the time the leading edge of the document passes through the detection part I, N
After counting only two pulses (the time for counting is inversely proportional to the document conveyance speed), the leading edge of the document is at the center A of the slit. So, at that time (second,
3) or after a certain period of time at any magnification from that time K (4th
Figure) By setting the leading edge of the copy material to a predetermined position or position E and waiting beforehand, the leading edge of the image can be aligned at OJ for all variable magnification copying by starting the conveyance toward the next process.
Becomes Noh. In addition, in the above FIG. 5, the pulse generating plate 45't
- Although it is provided coaxially with the roller 43, it does not necessarily have to be coaxially with the document transport roller 43 as long as it is synchronized with the conveyor stage. Furthermore, instead of the pulse generating plate 45 and the pulse detecting member 46, a combination of a rotating cam member provided via a clutch, a micro switcher, etc. may of course be used.

Also, when aligning the tips with higher precision, use hi 1st
The register row 242 described in FIG. 4 can be utilized. That is, the register roller 4 closer to the transfer section
2 is temporarily stopped from rotating just before it reaches the copy material 39O to prevent the copy material 39 from advancing, thereby creating slack in the copy material. Thereafter, when the roller 42 rotates again, the unstable conveyance movement of the copy material that occurred during conveyance is absorbed, and good leading edge alignment is achieved. - The signal controlling the row 242 is based on the signal when the original tip image is exposed to the photoreceptor. It is also possible to take out the signal separately from the conveyance start signal for the photographic material and use it by delaying the signal using a delay means such as a timer.

Furthermore, in this case as well, since the same delay means can control various types of variable-magnification copying, both the apparatus and the leg force method are extremely simple.

In any case, according to the present invention, there is no need to provide document detection means, delay circuits, etc. in the number corresponding to the selectable magnifications, and even in a multi-stage variable magnification pupil, the document image and the copy can be reproduced with a simple configuration. It is possible to match the ends of materials.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a copying box to which the present invention is applied, FIGS.
The figure shows a sectional view of a slit portion to which the present invention is applied. In the figure, 2......second exposure section, 4......
photosensitive drum. 13...Original, 16-2o...Curved conveyance low 2゜18...Glass plate, 22...
···lamp. 24...Lens, 39 songs/copying materials, 4
3.44...Song...Document transport roller, 45...
...Pulse generator board. 46... Pulse detection member, ■...
・Detection means position. Applicant Canon Co., Ltd.

Claims (1)

[Scope of Claims] A document conveying means for conveying the document at a speed corresponding to a selected magnification, and an optical means for projecting the image of the document at the selected magnification onto a photoreceptor that moves at the same speed regardless of the magnification. and,
In a variable magnification copying apparatus having a transfer means for transferring an original image formed on a photoreceptor to a copying material that moves at the same speed as the photoreceptor, an original detection means provided in an original transport path and an original document a feeding means a rotating member that rotates once at a speed corresponding to the selected magnification in conjunction with the selected magnification, and means for detecting the rotation of the eleven rotating member;
The apparatus detects that the rotating member rotates in the same manner regardless of the selected magnification from the time when the original detecting means detects the original, and sets the leading end position at a predetermined position in advance and waits. A variable magnification copying apparatus characterized in that the copying material that has been placed is started to be conveyed to a transfer position.