JPS6049360A - Method and device for frame erasure of copying machine - Google Patents

Abstract

PURPOSE:To eliminate completely a frame by blanking or black-erasure exposing the surface of a photosensitive body except in an original image projection area or at the area and the circumference of its boundary according to an input discrimination signal for the size and position of an original. CONSTITUTION:Resistance 14 and transistors (TR) 13 are connected to a microprocessor 10, and light emitting diode 11 are connected to the collector sides through resistances 12. The light emitting diodes 11 are connected to a power source and applied with a voltage Vcc, and arrayed in a line to constitute a light emitting diode array 15 as a blank and black erasure exposure source. A frame erasure switch 9 is selected and an original position is inputted to the microprocessor 10 by an original size and position input circuit 8 to select a frame erasure mode and take a copy. Consequently, even when the entire area of platen glass 1 are regarded as a copy image area in unmagnification copying operation, an actual copy area is developed as shown by slanting lines, and other parts are not developed because of black erasure exposure and blank exposure are applied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for erasing edges of a copying machine and a device thereof, in particular, a method for selecting the range of blackening by a blackening device in accordance with the size of the document and the position of the document on the document table glass. This article relates to a method for erasing edges and a device for erasing black lines.

Conventionally, in copying machines, static electricity is removed from the non-image area of the photoreceptor surface where the original image is not projected by blank exposure or exposure by light reflection from the original pressure bonding plate. In order to prevent stains, blackening was performed to prevent unnecessary areas from being developed in the next step.

Particularly when copying an original whose size is narrower than the image scanning area, when the original is placed on the platen glass, the area other than the area occupied by the original in the image scanning area is covered by the white surface of the lower surface of the original pressing plate. There is no problem because the photoreceptor corresponding to the receiving area is exposed by light reflection from this point on. However, if the document to be copied is a thick book, this document pressure plate will float around the book due to its thickness, and the white bottom surface cannot be flattened, so it will not be possible to flatten the white bottom surface of the document. The light reflected by the white lower surface of the crimp plate may be reflected in the wrong direction, or the edge of the book may be in the way, preventing sufficient light from hitting the white lower surface and exposing the light emitter. Since it is not possible to do so, black erasure becomes incomplete. Therefore, unnecessary ix development is performed and unnecessary developer is consumed, resulting in the formation of an annoying shadow on the copy paper on which the original image is copied.

Furthermore, misalignment between the developed powder image of the original formed on the photoreceptor and the copy paper does not necessarily occur due to the accuracy of the copying mechanism and misalignment when setting the original. Therefore, the edge of the original document may appear in shadow on the edge of the copied copy paper, which may be unsightly.

The present invention has been made in view of the above-mentioned points and to improve the above-mentioned drawbacks.The present invention has been made in view of the above-mentioned points and to improve the above-mentioned drawbacks. It is an object of the present invention to provide a method and apparatus for erasing edges of a copying machine that more completely erases edges.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a copying machine edge frame erasing method and apparatus according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the edge frame erasing of the copying machine according to the present invention, as seen from the scanning direction of the original, and FIG. 1(a) shows the copying state at the same magnification. The figure shown in FIG. 1(b) is a diagram showing the state of copying at the time of reduction/magnification.

In the figure, 1 is an original table glass, 2 is a photoreceptor, 3 is an imaging lens, 4 is an original, and L is the width of the photoreceptor 2 in the longitudinal direction. Note that a light source (not shown) for blank exposure, such as a light emitting diode element array, is provided over the width of the photoreceptor 2. When copying at the same size as shown in FIG. 1(a), when edge frame erasure is not selected, or when black frame erasure is selected and the position and size of the document are not input, the edge R' of the photoreceptor 2
A portion of the photoreceptor 2 with a width C1 from the point is exposed to black eraser, and y
A portion having a width C2 from the point is exposed to blackout. Further, when edge frame erasing is selected, the size and position of the original document 4 are input in advance before the copying command, so the photoreceptor 2 is subjected to blank exposure or the like in accordance with the size and position. That is, now,
Here, it is assumed that the edges of the glass platen 1 are at points P and R, respectively, and the side edges of the document 4 are at points 9 and R, respectively, on the glass platen 1, and these points P, Q, and R. The projection positions by the imaging lens 3 onto the photoreceptor 2 are defined as points P', Q', and R', respectively.

rz, point P', and point R' correspond to the edge of the photoreceptor 2, and the projected image of the original is located on the portion of the photoreceptor 2 between the point R' and the point Q'.

Then, the photoreceptor 2 is exposed to blackout from point R' with width C1, and width D1 (where D, = P'Q' + C2, where η is the distance between points p' and Q', and C2 is a small positive value), and black erasure exposure is performed from 22 points on the edge of the photoreceptor 2. In this way, the document 4 is blackened by a width Ct from the R' point and by a width C2 from the Q' point between the R' point and the Q' point of the photoconductor 2, which are projected onto the photoconductor 2 by the lens 3. Because it is exposed to light,
The edges of the original 4 do not appear in the copied image. Note that this width CI.

C2 is small, and document 4 corresponding to these widths
Since the image is small in the width of the edge portion of , the copied image of the document 4 is not affected by taking this width.

In the case of reduced magnification copying as shown in FIG. , R' point, P'
, R' point is the edge of the photoreceptor 2. Now, here, when the edge frame eraser is not selected, or when the edge frame eraser is selected but the document size and position are not input, the edge R of the photoconductor 2
The black erase exposure is performed from the point ' to the width C3, and the width C's (
However, 'L,,c5=P'P''+C41,=,:
The photoreceptor 2 is subjected to black erasure exposure from the green point P' (distance between the point V and the point C4, C4 is a small positive value). Furthermore, when edge frame erasing is selected, since the size and position of this original 4 have been input before the copying command, the photoreceptor 2 is subjected to black erasing exposure or the like in accordance with the size and position.

That is, the original 4 is placed between the Q" point and R' of the photoreceptor 2 by the lens 3.
Assuming that point-to-point projection is performed, the photoreceptor 2 is exposed to black by a width C3 from a point R' on its edge, mD4 ((E,
D4 = P'Q'' + C4, here, z is the distance between points P' and q'), and the photoreceptor 2 is exposed to black from the edge V point. In this case, the original 4 is also exposed to the imaging lens. Between the point R' and the point Q" of the photoconductor 2 projected onto the photoconductor by 3,
Since blackening exposure is performed by a width C3 from point R' and a width C2I from point 9, the edges of the original 4 and their shadows do not appear in the copied image. Also, as mentioned above, the direction perpendicular to the scanning direction (
= Not only is the exposure width taken to erase the black edges of the document 4, but the same thing as above is also performed for blank exposure to remove the influence of the edges of the document 4 in the direction perpendicular to the scanning direction. Therefore, even if you copy an original whose size is the same as the copy scanning area or narrower than the copy scanning area, or a particularly thick one (such as two copies), the edge of the original will not be affected by the edges of the copy. As mentioned above, the black erasure exposure and blank exposure are performed, for example, using a light emitting diode array. In FIG. The diode element array is perpendicular to this and near the top along the longitudinal width of the photoreceptor 2.

FIG. 2 shows a circuit diagram for controlling the lighting timing and lighting range for blank exposure and blackout exposure. In Figure 1, 5 is a detection circuit that detects when the scanning optical system has come to the reference position (hereinafter referred to as the image front position) on the document platen glass, and 6 is a detection circuit that detects the rotation of the photoreceptor (= the corresponding clock A drum clock pulse generation circuit generates pulses, 7 is a paper size input circuit for selecting and inputting the paper size as a transfer material in the cassette, 8 is a microcontroller for inputting the position and size of the original on the platen glass. A document size position input circuit is used to input data to the processor 10, and a border erase switch 9 is used to input to the microprocessor 10 whether or not to erase the border according to the document size and position. The signals output from the detection circuit 5 and the drum clock pulse generation circuit 6 are sent to the microprocessor 10.
The microprocessor 10 also inputs the drum
A control signal for controlling the clock pulse generation circuit 6 can be given. Also, microprocessor 1
0 includes respective resistors 14, respective emitter-grounded transistors 13 connected to these resistors 14, and these transistors 13 through an interface (not shown).
A light emitting diode 11 is connected to the collector side of each through a resistor 12, respectively.

The light emitting diodes 11 are commonly connected to the power supply and Vc
A DC voltage of c is applied thereto, and the light emitting diode elements array 15 is arranged in a straight line and serves as a blanking and blackening exposure source. rzOh, this light emitting diode element array 15 is arranged so that its longitudinal direction is located in a direction perpendicular to the scanning direction of the photoreceptor 2 shown in FIG. It is located near the top.

In FIG. 3, the position of a thick document such as a book placed on the document table glass 1 is indicated by a broken line. Further, near the edge of the lath 1 of this document table, scales are provided in the X-axis direction and the Y-axis direction, so that the operator can recognize data when inputting the position of the document. When the border eraser switch 9 is selected and the original position is input to the microprocessor 10 through the original size and position input circuit 8 shown in FIG. 2 as described later, and the border eraser is selected and a copy is made, if Even if the entire area of the original platen glass 1 is used as the copy image area during full-size copying, the actual area to be copied is the area up to the border slightly inside the edge of the original area indicated by the broken line, i.e. Only the shaded area is developed, and the other parts are exposed to black and blank and are not developed.That is, in the Y-axis direction,
The width at the position of the photoreceptor 2 corresponding to the width y1 and the width y2 of the document table glass 1 in the direction perpendicular to the document scanning direction can be understood as C1 in FIG. 1(a), respectively.

Figure 4 shows the size and position of the document described above in Figure 3.
FIG. 4 is an explanatory diagram for inputting information using the document size/position input circuit 8 shown in the figure.

The method for setting the size and position of the original is to determine the coordinates of the original on the original platen glass 1, as shown in Figure 3, and then (
- Numeric keys from 0 to 9 shown in Figure 4, selection keys for selecting the input of the position in the X-axis or Y-axis direction, keys for inputting the first and last positions of the document, input using these keys. Use the clear key to clear the data at the current position and reset the data input. Tl, you can press these keys to set the position of the original only when the copier is not copying, or even during copying when the scanning optical system finishes scanning the original and returns to the home position. This is possible when processing not directly related to the image format is being executed, such as when returning to a position.

For example, as shown by the broken line in FIG.
When a thick original is placed on the top, as shown in Figures 4 and 5 (-1, first press the large X direction key to turn it on.
→Next, input 30 with the numeric keypad 521→Next, press the start point key 522→Next, input 90 with the numeric keypad 523→Next, press the end point key 524. Finish inputting in the X direction 525° Next, press the large key in the Y direction 53
→Next, enter O with the numeric keypad 541→Next (2. Press the start point key 542→Next, enter 80 with the numeric keypad 543→Next, press the point key at end 1."g44,%Y Finish inputting the direction 54
5゜When the original is in the full width of the copying area in the X-axis direction or Y-axis direction, or when the edge of the original needs to be erased even if it is much smaller than the copying area, Since input in the Y-axis direction is not required, document position manual 1 or document position manual 2 is not executed. When performing normal copying, the large X-direction key 51 and the large Y-direction key 53 are not turned on, and both document position manual operations 1 and 2 are not executed. At this time, when copying, only the black border is erased according to the selected paper size.

Next, an embodiment of the operation of the present invention will be explained with reference to FIG. 1(a) and FIGS. 2 to 6.

As will be described later, the initial conditions of the document size position input circuit 8, border eraser switch 9, and copy magnification are input to the microprocessor 10 to input necessary initial information. Next, when the operator inputs a copying command, the photoreceptor 2 (actually (2 is a photoreceptor drum for electrophotography, but since the photoreceptor includes this, it is called photoreceptor 2) rotates forward, At this time, all the light emitting diode element rows 15 are turned on, and the photoreceptor 2 is exposed to blank light over the entire width (61 degrees) in the generatrix direction (direction perpendicular to the scanning direction).Next, the scanning optical system moves in the scanning direction. Then, the original 4 is exposed onto the photoreceptor 2 through the 1st lens 3. At this time, the image leading edge detection circuit 5 detects that the scanning optical system starts scanning and the original platen is at the reference position of the last 1. When the 62° scanning optical system that detects whether the position, that is, the continuous light position (2) has moved to the image front position, the drum clock pulse counter in the microprocessor 10 is cleared and
After 3, the clock pulses from the drum clock pulse circuit 6 are input and the clock pulses are counted.

When this count value reaches a predetermined value, it can be seen that the blank exposure position of the light emitting diode element array 15 has reached the corresponding position of the image tip on the photoreceptor 2. 65. Determine whether the frame erase selection switch 9 is turned on and selected.Here, there are three initial settings.

(1) In the first case, as shown in Fig. 3, the thick original 4 is moved away from the tip of the image, and the copying area (in this case, the entire area of the original platen glass 1 is assumed to be the copying area). .)
When the document table places the document 4 on the lath 1 and copies it in a narrower area, as described above, the document size and position are input from the original (1: G size/position input circuit 8 (2), and the Then, turn on the border eraser switch 9 and set the border eraser selection before issuing the copy command.

(2) In the second case, when the original is placed in the appropriate rz copying area on the original platen glass 1, for example, place the thick original 4 in the area indicated by the dashed line in FIG. 3 on the original platen glass 1. When the original 4 is placed, that is, when the edge of the original 4 is aligned with the image front position, which is the 0 position in the X direction, the edge frame eraser switch 9 is activated.
This is a case where the original size and position are not inputted using the original size/position input circuit 8.

(3) In the third case, when you want to copy a document of normal thickness by placing it on the entire copying area, in this case, you do not operate the document size/position input circuit 8, and you do not need to operate the edge frame eraser switch 9. Also keep it off.

The first case (1) and the second case (2) are when the edge frame eraser switch 9 is in the ON state, and in the first case (1), the original 4 is placed at the desired location on the original platen glass. In the second case (2), the edge frame eraser is selected but the position and size of the document 4 are unknown. Therefore, in the first case (
1) It is determined whether the leading edge of the latent image formed on the photoreceptor 2 through the imaging lens 3 by scanning the original 4 by the scanning optical system has reached the exposure position of the light emitting diode element array 15 67 This determination is made by counting the clock pulses from the drum clock pulse generating circuit 6 using the counter as described above, and determining whether or not this count value has reached a predetermined count value. If the leading edge of the latent image reaches the blank exposure position (68°), it is determined whether the photoconductor 2 has further rotated by the number of clock pulses The width in the circumferential direction of the rotation of the photoconductor 2 during pulse number time 1] corresponds to the width x1 of the document platen glass, which corresponds to the width of the latent image formed on the photoconductor 2. 1 scale width in the X-axis direction (30
-1-3: All charges on the photoreceptor 2 in the copy area up to I) are erased by blank exposure. Next, the light emitting diode element array 15 lights up according to the document position, size, and copying magnification.For example, in the case of full-size copying in FIG. 3, the document table corresponds to the width yl+y2 on the lath 1 in the Y-axis direction. In order to erase the partial charge on the photoreceptor 2, as shown in FIG.
The light emitting diodes corresponding to the exposure of width C1 and width D1 continue to light up, and the other light emitting diode element rows 15
The light-emitting diode is turned off and exposed to black. Next, it is determined whether the latent image formed on the photoreceptor 2 of the original 4 remains from the exposure position of the light emitting diode element array 15 for X clock pulses with respect to the rotation of the photoreceptor 2. The position corresponding to the position of the latent image on the original table glass 1 is the position of the (90"+) scale in the X-axis direction in FIG. 4. This remaining latent image on the photoreceptor has come to the blank exposure position. At this time, all the light emitting diode element arrays 15 are turned on again to perform blank exposure to erase the charge on the photoreceptor.71° Thus, as described above in FIG. A latent image remains on the photoreceptor only in the area where the photoreceptor is exposed, and is developed and visualized on the transfer material.The area near the broken line area, that is, the area near the edge of the document, and all other copy areas other than the shaded area are exposed. Therefore, the charge on the photoreceptor in that area is erased and is not developed.Therefore, this shaded area (
2. Only the latent image formed on the photoreceptor 2 is developed into a toner image, and this toner image is transferred to a transfer material of an appropriate size input by the paper size input circuit 7 corresponding to the toner image. After being transferred, it is fixed to complete the copying process. Note that the light emitting diode array 15 that lights up and blankly exposes the photoconductor 2 as described above further blankly exposes and then turns off at 73 degrees when the photoconductor 2 rotates backwards, whereas the initial setting is 73 degrees. In case 2 (2), the edge of document 4 is
As shown by the dashed line in the figure, the image is at the top position, so in order to erase the charge on the photoreceptor 2 corresponding to the width r:1 in the Determine whether the photoreceptor 2 has rotated by the number of pulses 77° At the point when the photoreceptor 2 has rotated, the light emitting diode element array 15 is activated to erase the black frame according to the transfer paper size selected by the paper size input circuit 7. In other words, when copying at the same size as the original size as in the first case, the width C1 of the photoreceptor 2 shown in FIG. 1(a) and 0
A light emitting diode corresponding to 2 is turned on to erase the black frame. Next, it is determined whether the rear end of the copy area of the photoreceptor 2, that is, the rear end of the paper used for transfer, remains for X number of clock pulses relative to the rotation of the photoreceptor 2 from the exposure position of the light emitting diode element array 15. 79° When a width corresponding to the number of clock pulses from the rear end of the paper remains from the exposure position of the light emitting diode element array 15, all the light emitting diode element arrays 15 are turned on again to blankly expose the photoreceptor 2 71 The subsequent steps are the same as in the first case, and their explanation will be omitted.

In the third case (3), the edge frame erasure selection switch 9 is
is in the off state (No judgment in 65), and the paper size selected and input by the paper size input circuit 7, that is, the predetermined selected copy area (for example, A4 size or B5 size) and the selected copy magnification The light emitting diodes of the predetermined light emitting diode element array 15 continue to light up. For example, in the case of a same-size copy, the width C1 on the photoreceptor 2 and 0
The light emitting diode at the position corresponding to 2 continues to light up for blackout exposure, and the other light emitting diode element rows 15
The light emitting diode of will turn off. Thereafter, the photoreceptor 2 continues to rotate, and when the trailing edge of the latent image of the original 4 on the photoreceptor reaches the blank exposure position, all the light emitting diodes in the light emitting diode element row 15 light up to blankly expose the photoreceptor 2. The copying process after 71° is substantially the same as in the first and second cases, and the explanation will be omitted.

In addition, in the above embodiment, the case of same-size copying was taken as an example, but
In the case of reduced-magnification copying, as shown in FIG.
, the width C4 may be used instead of the width C2, and that area may be exposed.

Note that, in addition to the edge of the document, for example, using the document 4' shown by the dashed line in FIG. 1(b), the width R5 of this document
is projected onto the width R/SJ of the photoreceptor 2, and if you want to copy only the width RQ of the original 4', the width C
3 and the width D4 (however, D, = P'Q"0 C4), if the part of the photoreceptor 2 is exposed to black, an image of only the part of the width QR of the original 4' will be developed. According to the invention, it is possible to develop only the necessary parts of the image of the document without focusing on the edges of the document.In this explanation, only the direction perpendicular to the scanning direction has been described, but the second direction can also be used in the scanning direction.
This can be carried out by the means described above in FIGS.

The interwoven process shown in FIG. 7 is executed when the drum tarlock pulse generating circuit 6, which generates pulses in proportion to the rotation angle of the photoreceptor 2, rises (or may fall or level). When an interconnect occurs, the counter area is increased by 1.8o0 By looking at the contents of this counter area, it is possible to know how far the photoconductor 2 has traveled from the position of the photoconductor 2 corresponding to the image tip position. ,
This can be used as a signal to determine timing.

In addition, in the above embodiment, a light emitting diode element array was used as the exposure source for blanking and blackening, but in addition to this,
A combination of a liquid crystal in which a large number of transparent electrodes are arranged one-dimensionally and an elongated light source surrounded by a light-shielding frame on the liquid crystal, or a light source provided with a shutter can be used.

In the above embodiment, the size and position of the document are input manually, but it is also possible to automatically detect and process the size and position of the document.

For example, a number of combinations of a point light source and a light-receiving element that receives light from which the projected light is reflected by the document are installed in a direction perpendicular to the scanning direction and above the scanning optical system. be installed on top of the reflective shade. by this,
When the scanning optical system scans for the first time after a copy command is issued, the light source of the scanning optical system is not turned on, and the combination of the point light source and the light receiving element is operated to automatically determine the size and position of the document. Detect accurately. Alternatively, a document feeder is used to automatically detect the document size when setting the document. The subsequent operation is substantially the same as that of the above embodiment, so a description thereof will be omitted.

As described above in detail about the present invention, when copying a thick original such as a book, the latent image near the edge of the original is erased by blackening and blank exposure is performed to erase the edge frame. We were able to remove unnecessary images caused by etc. Furthermore, the present invention is applicable not only to edge frame erasure but also to cases in which it is desired to take out and copy only the necessary portions of a document, and has the effect of making it possible to copy only the necessary portions of the document.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the relationship between the projection area of the original onto the photoreceptor and the blackening exposure area, FIG. 2 is a block diagram of the blackening device of the copying apparatus according to the present invention, and FIG. An explanatory diagram showing the dimensions of the original on the base glass, Figure 4 shows the size of the original, etc.
5 is a flowchart for inputting the document size and position; FIG. 6 is a flowchart for explaining the edge erasing method of the copying apparatus according to the present invention and the operation of the apparatus; FIG. 7 is a flowchart of the interlaced process shown in FIG. 1......Original table glass 2...Photoreceptor 3...Imaging lens 4.4'...Original 5 ..... Image edge detection circuit 6 ..... Drum clock pulse generation circuit 7 ..... Paper size input circuit 8 ....・
...Original size/position input circuit 9...
・Edge frame eraser switch 10・・・・・・Microprocessor 11・・・・・・Light emitting diode 15・
......A row of light emitting diode elements. (α) 1st (1)) Figure (C1) (b) Figure 5 (C)? =S 7th cause

Claims (2)

[Claims] (1) The document on the document table is exposed and scanned by the scanning optical system to form a projection area on the photoconductor, and the non-projection area of the photoconductor other than the projection area is exposed to light by an exposure source to eliminate static electricity, and then the projection area is In a copying method in which a latent image formed in an area is developed to form a developed powder image, the developed powder image is transferred onto a transfer material, and then this is fixed, edge frame erasure is selected. If done,
According to the size and position of the portion of the document to be copied on the document table, which is input to the control means for controlling the exposure width and exposure time of the exposure source, the photoreceptor is exposed by scanning the document by the scanning optical system. A method for erasing an edge frame, which comprises exposing an area of the photoreceptor other than an area slightly inside the projection area of the portion to be copied within a projection area formed in the area. (2) A document table on which a document is placed, a photoconductor, a scanning optical system that scans the document and exposes the document image onto the photoconductor with slit light, and a non-projection area of the photoconductor that is exposed to light to remove static electricity. In a copying apparatus equipped with an exposure source and a control means for controlling the exposure time and exposure width by the exposure source, the size of the portion of the document to be copied on the document table and the position thereof on the document table are determined. The edge frame erasing selection means includes an original area input means for inputting data into the control means, and an edge frame erasing selection means for selecting whether or not to perform edge erasing exposure in accordance with the information input by the original area input means, and the edge frame erasing selection means When erasing is selected, the area of the original projected on the photoreceptor formed by exposure scanning of the original by the scanning optical system is erased according to the information input by the original area input means. An edge frame erasing device for a copying apparatus, characterized in that an area of the photoreceptor other than an area slightly inside a projection area of a portion to be copied is exposed by the exposure source.