JPH0314184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a registration correction method in a copying machine.

The document image is scanned by relative movement of the document scanning system to the document, and a variable magnification image of the document image is formed on a photoreceptor with a size corresponding to the variable magnification ratio, and the variable magnification image is transferred to transfer paper. A variable-magnification copying method that involves transfer is known. Methods for transferring variable magnification images can be roughly divided into two methods: those that transfer an electrostatic latent image, and those that transfer a visible image of this. An image is formed on a photoreceptor and transferred to transfer paper. In the following explanation, for convenience, a visible image transfer method will be used.

By the way, out of the entire range of the original image, specify a copy portion of a desired width in a direction orthogonal to the moving direction of the original scanning system at a desired position in the moving direction, and then perform scaling based on this portion. make copies,
This may be provided for editing functions, etc. for example,
There are cases where a certain width of a character image part of a book or the like is specified and this part is enlarged or reduced in size and copied to perform various editing operations.

For example, in FIG. 1a, out of the entire range of the original image of the original O, a copy portion of a desired width in a direction orthogonal to the moving direction of the scanning optical system 1, which is an example of an original scanning system, is copied into the image portion 2. Specify selectively as in Figure a shows an example where the image portion 2 is shifted to the right side in the figure. Now, suppose that the scanning optical system 1 is moved in the direction of the arrow to scan the document image, and a designated image portion 2 of the document image is scanned.
is magnified, for example, into an enlarged image 2', which is imaged on a photoreceptor (not shown). Now, it is assumed that the enlarged image 2' has already been visualized, and this enlarged visible image is located at a distance determined by the magnification ratio from the center of the image portion 2.

Here, in FIG. 1a, d is referred to as the document reference edge. Now, since the image part 2 on the original is close to one edge of the original (original reference edge), we will use a transfer paper S that is smaller than the original and align one end of this transfer paper to the original reference edge d. In this case, a portion of the image 2' on the photoreceptor will protrude from the transfer paper. That is, if copying is performed assuming that the image 2' is placed on the transfer paper, a portion of the copied image will protrude from the transfer paper.

On the other hand, as shown in FIG. 1b, when the image portion 2 to be copied is on the left side in the figure, the enlarged image 2' on the photoreceptor is separated from the center of the image portion 2 by a distance determined by the magnification ratio. Since it is formed at the position shown in the figure, move the transfer paper S to the original reference edge d as in the case of figure a.
If you want to match the size, transfer paper S of a certain size
In this case, most of the enlarged image 2', which is the part to be copied, protrudes from the transfer paper S, making it impossible to achieve the desired purpose. A solution to this problem is to shift the original O to the right in the diagram, but this method not only requires extra work but also results in unnecessary copying. Become.

Therefore, as shown in FIG. ' can be stored in the transfer paper S. That is, the position of the image forming 2' on the photoreceptor,
The purpose is achieved by adjusting the mutual positional relationship with the position of the transfer paper S. Note that FIG. c shows an example in which the center of the transfer paper S corresponds to the center of the variable magnification enlarged image 2' on the photoreceptor.

The above is a case of enlarged copying, but the same can be said for reduced copying. In FIG. 2a, an image 3 of a copy portion of a desired width out of the entire range of the original image of the original O is reduced to a reduced image 3', and this reduced image 3' is formed on a photoreceptor,
This is transferred onto transfer paper S. In this case, assuming that the transfer paper S is aligned with the document reference edge d, the image 3' can be contained within the transfer paper S as shown in the figure, depending on the size of the transfer paper. In the case of Figure a, the image portion 3 is on the right side in the figure, but on the other hand, as shown in Figure b, when the image portion 3 is on the left side, the transfer paper S is aligned with the document reference edge d. , the reduced image 3' will protrude from the transfer paper S of a certain size. Therefore, as shown in Figure c, by shifting the transfer paper S from the virtual line to the solid line position, the reduced image 3' can be contained within the transfer paper. In this example as well, the center of the transfer paper S corresponds to the center of the variable-magnification reduced image 3'. In this way, for example, the desired purpose is achieved by shifting the transfer paper with respect to the variable magnification image formed on the photoreceptor, but the amount of shift is determined by the desired width. It varies depending on the specified position of the copying section, the magnification ratio, and the size of the transfer paper used.

In each case of enlargement or reduction copying, this problem occurs because the distance between the document reference edge d and the center of the image is intuitively determined on the photoreceptor when the distance is changed. This is because it is difficult to understand. Also, even if the copy image is at least inside the transfer paper,
If the copy image is shifted to the right or left side of the transfer paper, there is a drawback that it is difficult to see. In addition, when using the smallest possible transfer paper, it is necessary to move the original to the right as mentioned above, and even when copying is performed using the small transfer paper, the entire desired area is not transferred. If it does not fit on the paper, it is necessary to switch to a larger transfer paper size and copy, making the copying process extremely complicated. This problem can be solved, for example, by adjusting the resist so that the center of the transfer paper is aligned with the center of the image on the photoreceptor.

Regarding the above points, the same applies not only to variable size copying but also to same size copying, and can be solved by performing the registration adjustment described above. In this case, the shift amount is determined by , and the size of the transfer paper used.

The present invention solves these problems, and includes:
It is an object of the present invention to provide a registration correction method for a copying machine that can obtain a copy image of a portion of a document corresponding to a copy portion of a desired width.

The present invention will be explained below with reference to the figures from FIG. 3 onwards. FIG. By selectively pressing one,
The desired magnification is specified. FIG. 4 shows another example of means, in which the variable magnification ratio is designated by sliding the variable magnification ratio designation knob 6 in the horizontal direction.

On the other hand, for specifying a copy portion of a desired width in a document, the means shown in FIGS. 5 and 6, for example, is used. In the example shown in FIG. 5a, a scale is provided at the bottom of the contact glass 7, and first,
When placing a book or a sheet-like original O on the contact glass 7 and specifying the original image part in the range from scale 6 to scale 18, press the key switch on the keyboard 9 shown in FIG. Press in the order shown.

Here, the image end 10a on the left side of the desired copy surface image 10 in the document O is referred to as the left end, and the image end 10b on the right side is referred to as the right end. That is, regarding the desired image, the left end 10a corresponds to the scale 18, and the right end 10b corresponds to the scale 18.
When corresponds to scale 6, the key switches are pressed in the order shown in FIG. 7a, for example. In addition,
The key switch 9a is for pointing to the left end, and the key switch 9b is for pointing to the right end. In addition, Fig. 7b
The key switch operations may be performed in the order shown. Alternatively, a key switch as shown by reference numeral 9c in FIG. 6 may be provided and the key switch operations may be performed in the order shown in FIG. 7c. In addition, in Fig. 5b, when the scale is divided into three parts such as a, b, and c, and the left end of the desired image is designated as 1 on scale c, and the right end is designated as 4 on scale b, the 6th Using the keyboard 9 shown in Figure 7 d.
Perform key switch operations in the order shown.

If you accidentally reverse the order of key switches 9a, 9b, etc., the input value data will be automatically corrected in the arithmetic unit that processes these input values (this will be explained later). You may also do so. The example shown in FIG. 8 is provided with a group of key switches 11. For example, the switches 11a to 11d are depressed in sequence to designate the width of the desired copy area. In this case, turn the switch from 11d to 11a,
It may also be pressed down. As described above, the magnification ratio and the desired area to be copied are respectively specified.

FIG. 9 shows the basic configuration of an example of a variable magnification copying machine suitable for carrying out the present invention, in which an original O _B on a contact glass 12 is slit-shaped by an original illumination lamp 13. The reflected light from the original is reflected by the first mirror 14 and the second mirror 1.
5. The light enters the imaging lens 17 via the third mirror 16, and the light emitted from the imaging lens 17 passes through the fourth mirror 18 and is converted into imaging light onto the drum-shaped photoreceptor 19.
is administered and exposure is performed. Note that when scanning a document, the lamp 13 and the first mirror 1
4, and the first and second mirrors 15 and 16 move in the direction of the arrow at a speed ratio of 2:1, respectively. On the other hand, the fourth mirror 1
8 is fixed.

Now, in such a copying machine, when performing reduction copying, for example, both mirrors 15 and 16 are moved from the equal magnification position shown by the solid line to the imaginary line position, and the imaging lens 17 is moved from the same magnification position shown by the solid line. The optical conjugate length at the time of reduction copying with respect to the time of full-size copying is satisfied by displacing it from the position to the virtual line position. In addition, when performing enlarged copying, both mirrors 15,
16 to the left with respect to the same-magnification position indicated by the solid line, and the imaging lens 17 to the right relative to the same-magnification position indicated by the solid line. Note that each displacement amount is uniquely determined from the basic optical relational expression, so the explanation thereof will be omitted here.

In FIG. 10, the original illumination lamp 13 and the first mirror 14 are integrated and mounted on the first carriage 21. As shown in FIG. Similarly, the second mirror 1
5 and the third mirror 16 are integrated, and the second
It is equipped on Carriage 22. Here, the first
It is assumed that the carriage 21 is placed at position A, which is the home position, and the second carriage 22
It is assumed that the imaging lens 17 is located at a position determined by the variable magnification m. Note that when m>1, it is an enlarged copy, and when m<1, it is a reduced copy.

Now, assuming that the drum-shaped photoreceptor 19 rotates at a peripheral speed V in the direction of the arrow, the first and second carriages 21 and 22 are rotated at V/m and V/2m, respectively.
move at a speed of In the figure, L ₁ indicates that when the scanning optical system starts moving from home position A, it does not immediately move at a constant velocity due to its inertia, and even if the illumination lamp is turned on. This is the run-up distance of the scanning optical system, which was set in consideration of the fact that the illuminance may not stabilize immediately.

In FIG. 10, A is the home position as described above, and B is the document scanning start position, that is, the near end of the document. Further, L ₁ is the run-up distance as described above, and L ₄ is the scanning length of the document. Here, now from home position A to L ₂
Assume that a document image area having a width of L ₃ in ranges C and D, which are separated by a distance, is selected and specified from the document.
When a document is scanned under such conditions, an image 24 with a magnification ratio m is formed on the photoreceptor 19.
It is assumed that this has already been made into a visible image by the developing device 23, and this visible image will hereinafter be referred to as a variable magnification for convenience. Then, the above A, B, C,
D corresponds to A', B', C', and D', respectively, on the photoreceptor.

Now, the photoreceptor 19 is rotating at a circumferential speed of V,
During this rotation, when the detection cam 26 provided on the drum shaft turns on the switch 27, the first and second
Assuming that the carriages 21 and 22 start moving, the distance L ₉ from point A' to point B' on the photoreceptor is as follows.

L ₉ = VL ₁ / (V/m) = L ₁ m (L ₁ ≧0) That is, L ₉ is proportional to the product of the magnification m and L ₁ , and now,
If L ₁ (run-up distance) is a fixed length, L ₉ will be directly proportional to the magnification ratio m. In other words, _L9 changes depending on the magnification ratio m. in the same way
The distance from A' to C' is L ₂ m, and the distance from C' to D', which is the desired area to be copied, is L ₃ m.
Furthermore, the length of the variable magnification image 24 on the photoreceptor is L ₄ m.

Here, assuming that copying is performed on the transfer paper S fed by the registration roller pair 28 at the transfer position E, the time t ₁ for point A' on the photoreceptor to reach the transfer position E is L ₈ / It is V. Further, the time _t2 at which the image forming end B' corresponding to the front end B of the document reaches the transfer position E is as follows.

t ₂ = t ₁ +L ₉ /V=L ₈ /V+L ₁ m/V=Const+(L ₁ /V)
Since m, that is, L ₁ /V is constant, time t ₂ is proportional to the magnification ratio m.

Furthermore, the magnification ratio is m, and the first and second
The carriages 21 and 22 have V/m and V/m, respectively.
Each moves at a speed of 2 m, and the photoreceptor 19
Assuming that C rotates at a circumferential speed V, the time t ₃ for one end C' of a variable magnification image having a width of L ₃ m to be copied to reach the transfer position E is as follows.

t ₃ = t ₁ +L ₂ m/V=L ₈ /V+L ₂ m/V In other words, after the first carriage 21 starts the home position A, t ₃ hours, which is uniquely determined by the above formula, , the leading edge of the transfer paper S is at the transfer position E.
If the rotation start timing of the pair of registration rollers 28 is set so as to reach , as shown in _FIG . There is a correspondence match with C′. That is, in the case of Fig. 11, the width is at least L ₃ m.
A variable magnification image of 1 can be stored in the transfer paper S.

In the case of Fig. 11, one end C' on the variable magnification image and the leading edge of the transfer paper S are aligned,
As shown in FIG. 12, the rear end of the transfer paper S and the other end of the variable magnification image with a width of L ₃ m to be copied.
It is also possible to match D′. Now, let the length of the transfer paper S used be l _T , and from the leading edge of the transfer paper, there is a
Letting the distance to point A′ be X, then X=l _T −(L ₂ +L ₃ )m. That is, the rotation start timing of the pair of registration rollers 28 is set so that the leading edge of the transfer paper S reaches the transfer position E after ₄ hours t after the first carriage 21 starts the home position A. If determined, D' on the variable magnification image can be made to correspond to the trailing edge of the transfer paper.

t ₄ = t ₁ −X/V=t ₁ −l _T −(L ₂ +L ₃ )m/V=
L ₈ /V−l _T −(L ₂ +L ₃ ) m/V In other words, after the first carriage 21 starts from home position A, after a time determined in the range of t ₃ and t ₄ , the leading edge of the transfer paper The rotation start timing of the pair of registration rollers 28 may be determined so that the rotation of the registration roller pair 28 reaches the transfer position E, and under this condition, a desired magnification ratio can be accommodated within the transfer paper.

FIG. 13 shows an example in which the center of the transfer paper S is aligned with the center of the desired variable magnification with a width of L ₃ m. From the leading edge of the transfer paper,
Letting the distance to point A' be X, then X=l _T /2-(L ₂ m + L ₃ m/2). That is, after the first carriage 21 starts from the home position A, the leading edge of the transfer paper S reaches the transfer position E after ₅ hours t, as described below.
By determining the rotation start timing of the pair of registration rollers 28, it is possible to align the transfer paper S to the center position of a variable magnification image having a width of L ₃ m.

_t5 = _t1 −X/V= _L8 /V−l _T /2−( _L2 m+ _L3 m
/2)/V In addition, the length l _T of the transfer paper S is at least L ₃ m.
It only needs to be slightly longer than the width of the transfer paper, and as long as it is longer than this length, any size of transfer paper can be selected.

By the way, in FIG. 14, when the surface of the photoreceptor is uniformly charged by the charger 29, a range of length G is charged taking into consideration the rise of the charge and the like. Therefore, in the G range, a charge is applied and toner adheres during development. Now, let's use the transfer paper as the first
If the alignment method shown in FIG. 2 or FIG. 13 is used, toner in the range G will adhere to the transfer paper.

From this point of view, it is more advantageous to use the alignment method shown in FIG.
Even in the systems shown in FIGS. 13 and 13, the above-mentioned problem can be avoided if a short transfer paper is selected. In addition, as shown in FIG.
The present invention is also applied to the case where an image portion in a desired range of height H is scaled and transferred to transfer paper S in the image.

Now, as a method for registration correction of the mutual relationship between the variable magnification image forming position on the photoconductor and the position of the transfer paper with respect to this image forming position, in addition to moving the transfer paper in the register, there are two methods: The start timing of the scanning optical system of the copying machine may be changed.Furthermore, the copying machine is not equipped with a pair of registration rollers, and the paper feed cassette section directly
In the case where the paper feeding timing is set, the registration correction may be performed in the cassette section. In addition, in a system in which the optical system is fixed and a sheet-like original is moved on a contact glass, registration correction can be performed by changing the timing of transporting the original.

As described above, by adjusting the mutual positional relationship between the image forming position on the photoconductor corresponding to the desired copy area and the transfer paper, an image of the desired width (on the photoconductor) can be created within the transfer paper. can be accommodated in In this case, if the desired width is small, the size of the transfer paper can be changed to a smaller one, and in this case,
There is no need for any position adjustment work of the original.

Note that the present invention can be applied not only to variable size copying but also to same size copying.
The center of the desired image portion on the original corresponds to the center of the desired image on the photoreceptor.

Note that in a copying machine that uses only one size of transfer paper to make copies, there is no need to select a transfer paper, and the registration method for the transfer paper is simpler. In addition, in the case of a copying machine that uses transfer paper of various sizes, when selecting the transfer paper, it is also possible to decide the transfer paper in consideration of the range to be copied.

In addition, in corona separation or claw separation type copying machines, the leading edge of the transfer paper for separation becomes a margin area as an untransferred area, so in the present invention, the effective transfer area excluding the margin area is Adjust the resist so that the variable magnification image is transferred to the image. Note that registration correction can be performed using a pair of registration rollers or the like by arithmetic processing of factors such as the designated position of the desired copying area, the magnification ratio, and the designated size of the transfer paper using an appropriate arithmetic device.

According to the present invention, out of the entire range of the original image,
If you selectively specify a copy portion of a desired width in a direction perpendicular to the moving direction of the original scanning system at a desired position in the moving direction, the , it is possible to provide a registration correction method for a copying machine, which allows an image on a photoreceptor corresponding to the specified location to be contained within a transfer sheet. It goes without saying that the present invention can be applied not only to the visible image transfer method but also to the electrostatic latent image transfer method.

[Brief explanation of the drawing]

FIGS. 1 and 2 a to c are diagrams for explaining the problems of the present invention, FIGS. 3 and 4 are diagrams showing an example of variable magnification copy rate designating means, and FIG. 5 a
and b are diagrams each showing an example of means for specifying the desired copy area, FIG. 6 is a diagram showing an example of a keyboard for specifying the desired copy area, FIGS. 7 a to d are diagrams showing the key switch pressing procedure, FIG. 8 is a diagram showing another example of a means for specifying a desired area to be copied, FIG. 9 is a schematic diagram of an example of a variable magnification copying machine to which the method of the present invention is applied, and FIG. 11 to 13 are diagrams for explaining the registration adjustment of the transfer paper for the variable magnification image on the photoconductor, and FIG. The figure is an explanatory diagram of charging the photoreceptor portion in front of the effective magnification image area in order to take into account the rise of the charging charge. Figure 15 is an image portion of the desired height in the original image. FIG. 3 is an explanatory diagram regarding transferring the image to a transfer paper. 19... Photoreceptor, 21, 22... Original scanning system,
O...Manuscript, S...Transfer paper.

Claims (1)

[Scope of Claims] 1. A document image is scanned by relative movement of a document scanning system to the document, an image corresponding to the document image is formed on a photoreceptor, and the image formed on the photoreceptor is transferred to a transfer paper. In a copying machine for transferring, an area of a desired width in the moving direction of the original scanning system is designated as a copying part out of the entire range of the original image, and an image on the photoreceptor corresponding to the designated copying part is Select a transfer paper that can transfer all of the portion, and at the transfer position, the center of the selected transfer paper with respect to the conveyance direction coincides with the center of the image portion on the photoreceptor with respect to the photoreceptor movement direction. A registration correction method comprising adjusting the timing of transporting the transfer paper to the transfer position.