JPH0434747B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a copying apparatus that performs copying by scanning an original scanning means formed by a reciprocating means such as an optical unit or an original placing table.

<Summary of the Invention> The present invention includes a document scanning device consisting of a reciprocating means such as an optical unit or a document table, and conveys the copy paper at the timing when the center of the copy paper coincides with the center of the image on the photosensitive drum. In addition to making it possible to copy an image in the center of the copy paper, the document scanning means is set to 1 of the sum of the length of the document in the conveyance direction and the length of the copy paper in the conveyance direction divided by the copying magnification. It scans a distance equivalent to /2.

<Prior art and its disadvantages> Conventionally, when copying a document, it is common to align the leading edge of the copy paper with the leading edge of the image, but it is common practice to align the leading edge of the copy paper with the leading edge of the image. Copying images so that they match is effective in image editing and the like. However, in the past, it has not been possible to efficiently place a document in a predetermined position and copy it onto a copy sheet of any size at any magnification at the center of the copy sheet.

<Objective of the Invention> An object of the present invention is to solve the above-mentioned problems and to provide a copying apparatus that is capable of efficiently copying at any magnification in the center of a copy sheet.

<Structure of the Invention> (a) Principle FIG. 5 shows the relationship between the original and the image on the photosensitive drum at each copying magnification. As is clear from the figure, when the lens is at position A, the image on the photosensitive drum is a-a', when the lens is at position B, it is b-b', and when the lens is at position C, the image is a-a'. has an image size of c−c′.

FIGS. 6 and 7 show the relationship between such an image and the scanning distance of copy paper and original scanning means. As shown in FIG. 6, when the size of the image is smaller than the size S of the copy paper, the optical unit scans the image by a distance corresponding to the size of the image, that is, a distance of the document size D, and scans the image at the center of the copy paper. Images can be transferred. As shown in FIG. 7, when the image size on the photosensitive drum is larger than the copy paper size S, the distance corresponding to I/2 is required to expose the first half of the image (the left half in the figure) onto the photosensitive drum. That is, it is necessary to scan the optical unit at a distance of D/2. However, for the second half (right half) of the image, it is only necessary to expose the image necessary to transfer it to the second half (right half) of the copy paper, so the scanning distance of the optical unit is set at m
Then, it becomes S/2m. Therefore, the scanning distance of the entire optical unit is (D+S/m)/2.

(b) Structure of the invention Image size I (I=
means for conveying the copy paper at a timing when the center of the image size I is equal to or smaller than the copy paper size S (I
≦S), the document scanning distance by the document scanning means is set to a distance corresponding to the length D of the document in the scanning direction, and the image size I is larger than the copy paper size S (I>S). In this case, the document scanning distance by the document scanning means is 1/2 of the sum of the length D of the document in the scanning direction and the length S of the copy paper in the conveying direction divided by the copying magnification m. The distance corresponding to (D+
s/m)/2; and means for prohibiting copying when the set distance exceeds an effective scanning distance LO of the document scanning means determined by a magnification. shall be.

<Example> (a) Principle of operation The basic principle of the present invention is that when the original scanning means such as the optical unit is scanned, the time required to reach a reference position such as the leading edge position of the original after its activation is determined. Therefore, it is possible to transport the copy paper before the document scanning means reaches a constant speed.

FIG. 3 is a diagram for explaining the configuration and operation of the optical system movable copying apparatus. In the figure, an optical unit is constituted by a first mirror 1, a second mirror 2, and a third mirror 3, and the original is scanned by scanning the original placing table 7 with this optical unit. 6 is a photosensitive drum, and PSC is a paper start clutch, at which point the copy paper is temporarily stopped and conveyed at a predetermined timing. In such a configuration, the copy paper is conveyed at a timing when the center of the image on the photosensitive drum coincides with the center of the copy paper. This timing is the distance l1 from the exposure position P4 of the photosensitive drum 6 to the transfer position P5.
It can be determined based on the distance l2 from the position P6 of the PSC to the transfer position P5, the transport speed V0 of the copy paper, and the time from when the first mirror is activated until the document is scanned to the leading edge position P2.

Since the scanning speed of the document scanning means differs depending on the copying magnification of the document to be copied, the time it takes for the document scanning means to reach a reference position such as the leading edge position of the document from the home position differs depending on the copying magnification.

FIG. 1 shows an example. In the figure
Vm1 is the scanning speed of the document scanning means when the copying magnification is the maximum, and Vm2 is the scanning speed of the document scanning means when the copying magnification is the minimum. As is clear from the figure, the faster the scanning speed is, the earlier the constant speed is reached due to the drive characteristics of the document scanning means. HPS is a home position switch, which is turned off when the document scanning means exceeds the home position. EP is a detection pulse of a rotating slit disk (rotary encoder) attached to the drive system that drives the original scanning means, and after the original scanning means is started and the HPS is turned off, the number of pulses is counted. , n becomes the reference position.
In other words, Tm1 is the acceleration time from when the original scanning means starts its operation until it reaches the reference position when the copying magnification is the maximum magnification, and Tm2 is the acceleration time from when the original scanning means starts its operation when the copying magnification is the minimum magnification. Each represents the acceleration time to reach the position.

By determining the time required for the document scanning means to reach the reference position in accordance with at least two different copying magnifications, the acceleration time at any copying magnification can be determined.

FIG. 2 shows the method. As is clear from the figure, the copying magnification and acceleration time are expressed by a linear function, and the acceleration time Tm at any copying magnification m can be determined by the following equation.

Tm=Tm1+(Tm1-Tm2)×(m-m1)/(m1-m2) During the acceleration time determined in this way, the exposure position on the photoreceptor drum (P4 in Figure 3) changes to the transfer position (P4).
5) The conveyance timing of the copy paper can be set based on the time added to the time required to reach 5). That is, if the time difference between the timing at which the document scanning means starts its operation and the timing at which the copy sheet is conveyed is ΔT, it can be determined by the following equation.

ΔT=Tm+(l1-l)/V0-(1) Here, l1 and l2 are the distances shown in FIG. 3 as described above, and V0 is the peripheral speed of the photosensitive drum, that is, the copy paper conveyance speed.

Since the transfer position on the copy paper is determined by such a time relationship, if the conveyance timing of the copy paper is controlled by adding or subtracting the time required to further shift the image to this time, the desired copy image can be achieved. Can make shifts.

For example, if the distance to be shifted is SH, the time required for copy paper to travel that distance is SH/
It is V0. Therefore, the timing of conveying the copy paper is determined by the following equation.

ΔTS = ΔT-SH/V0 - (2) Therefore, when copying in the center of copy paper (centering), let the original size (width in the scanning direction) be D, the copy paper size S, and the copy magnification m. For example, the time from the leading edge of the copy paper to the leading edge of the image to be copied is calculated as (S-m×D)/2V0. Therefore, the timing of conveying the copy paper can be determined by the following equation.

ΔTC=ΔT−(S−m×D)/2V0
-(3) By the way, when making enlarged copies, the zoom lens 5
moves to the position shown at 5'. Therefore, when the third mirror 3 reaches the right side at the maximum magnification, the lens and the third mirror will be closest to each other. However, if the distance between the third mirror and the lens is designed based on the document size and copying magnification that are often used in practice in order to miniaturize the device, the scanning distance of the document scanning means will be limited by the copying magnification. .

If this scanning distance is defined as the effective scanning distance L0, it is automatically determined before the copying operation whether the document scanning distance described above does not exceed this L0, and copying is prohibited when it exceeds this.

(b) Specific Example FIG. 8 is a block diagram of a control section of a copying apparatus according to the present invention.

The microcomputer 20 performs predetermined control according to a control program stored in the ROM 21 in advance. The RAM 22 is used as a buffer memory and an area for flags and other calculations. 25 is a signal input device such as a key switch or a copy paper detection switch; 251 is a key for instructing copying to transfer an image to the center of the copy paper (hereinafter referred to as centering); and 252 is a key for instructing copying to transfer an image to the center of the copy paper; and 252 is a signal input device such as a copy paper detection switch. This is a key for instructing to shift. 23 is an interface circuit for this signal input device. 26 is a display control circuit (driver array) for displaying copying magnification and other various displays, and 24 is an interface circuit thereof.

FIG. 9A is a flowchart for determining the time required to reach the reference position after the document scanning means starts scanning for two different copying magnifications as shown in FIGS. 1 and 2.

First, if the copying machine is turned on, go to step
Clear the memory at n10 (hereinafter the step numbers are simply indicated by their numbers), return the optical unit to the home position at n11, and initialize the counter representing that position (MM means mirror motor). . At n12, the control pattern for the copy magnification m1 is read from the memory. This control pattern is control data that is predetermined according to the copy magnification.
Scanning by the document scanning means is performed based on this data. That is, first, n13 turns on the motor that drives the optical unit, and n14 turns on the timer.
Reset the TM and start. n15 is for determining whether the value of the counter C has reached a predetermined number n. At n16, it is determined whether or not the encode pulse EP shown in FIG. 1 is generated. If EP is generated, the counter is incremented at n17. That is, through steps n15 to n17, counting is performed until the number of encode pulses EP reaches n. n18 is brag F1
This is to determine whether or not it is in the set state. Initially F1 is in a reset state. For this reason, flag F1 is first set at n19, and timer TM is set at n20.
The value of , ie, the time required to exit the loop of steps n15 to n17, is stored in the memory MA. The value of this timer corresponds to the value of Tm1 shown in FIG. 1 above.

n21 is a process to confirm that the optical unit has reached a constant speed. However, since it usually reaches a constant speed, it immediately moves to n24. Step n24 waits until the optical unit drive system stabilizes, and then steps n25 and n26 return the optical unit to its home position.

At n27, the flag F2 is determined, but at this point it is in a reset state, so the process returns to n13.
Therefore, the same operation as above is performed, but since the flag F1 is already set at this point, this is determined at n18, and the timer value is stored in the memory at n22.
Store in MB. This is determined at n27 by setting the flag F2 at n23, and at n28 the average of the values stored in the memories MA and MB is calculated and that value is input to Tm1. This means that the average acceleration time of the document scanning means when the copying magnification is m1 is determined. n29 performs the same processing as described above with the copying magnification m2. Average acceleration time at copying magnification m2
Find it as Tm2.

FIG. 4 shows a preliminary scanning speed pattern of the original scanning means (optical unit). In the figure, V1 represents the scanning speed at copying magnification m1, V2 represents the scanning speed at copying magnification m2, and Vr represents the speed at which the optical unit returns. still
HPS is the home position switch signal.
The reason why the return speed is constant regardless of the copying magnification is that the return speed does not contribute to the image forming process.

FIG. 9B shows the process following the preliminary scanning described above, in which the fixing roller is first warmed up at n30, and the various parts of the copying mechanism in the copying apparatus are initialized at n31. Thereafter, at n32, the ready lamp indicating the copy-ready state is turned on. n33 reads inputs such as original size D, copy magnification m, copy paper size S, centering designation CNT, and shift designation. Each of these data can be input from the keyboard or automatically detected. n50
Based on these read data, processing is performed to determine whether copying is possible and the time required for scanning by the document scanning means. (This process is explained in FIG. 13). At n34, it is determined whether or not the print switch has been operated. If the print switch has been operated, the ready lamp is turned off at n35, and the paper feed roller (paper feed solenoid) is driven at n36. Calculate ΔT at n37. This value is calculated based on the above equation (1). n38 and n39 are for determining whether the copying process is centering processing, shift copying, or normal copying.

FIG. 10 shows the processing procedure in normal copying.

First, the state of the paper detection switch MS1 is determined at n60. This detection switch detects whether or not the copy paper is in contact with the PSC (paper start clutch) position shown in Figure 3. If the copy paper is in contact with the PSC, the optical Start scanning the unit and turn on the copy lamp on n62. Thereafter, in n63, the process waits for the time ΔT already determined. After ΔT time elapses
Turn on PSC on n64. That is, the copy paper is conveyed at this timing. n65 is a process from transferring an image to the transported copy paper to finally ejecting the paper to a paper ejection tray. n66 determines whether all copies have been completed for the number of copies to be made; if not, n67 drives the paper feed roller (PFS in Figure 3), and returns to n60 to perform the same process. . Once all the copying processes are completed, the 9th
Return to step n33 in Figure B. In this way, normal copying can be performed by starting the operation of the optical unit and transporting the copy paper after ΔT.

FIG. 11 is a flowchart showing the processing procedure for centering copying.

First, n70 calculates ΔTC. This ΔTC is calculated by the above equation (3). If the value is negative, the state of the paper detection switch MS1 is first determined at n72, and if the copy paper is already in contact with the PSC, the PSC is turned on at n73 to start conveying the copy paper. At n74, the process waits for the already determined ΔTC (absolute value), and after that time has elapsed, scanning of the optical unit is started at n75, and the copy lamp is turned on at n76. n77 is a process from transferring an image to the transported copy paper to finally ejecting the paper to a paper ejection tray. Similarly to the case of FIG. 10, n78 and n79 are for determining whether the number of copies to be made has been completed and for feeding paper for the next copy.

In this way, when ΔTC is negative, the image can be transferred to the center of the copy paper by conveying the copy paper and scanning the optical unit after ΔTC has elapsed.

If ΔTC is 0 or more, the copy paper is first
Determine whether it is in contact with the PSC, start scanning the optical unit at n81, and turn on the copy lamp at n82. Thereafter, at n83, the process waits for a time of ΔTC, and after ΔTC has elapsed, at n84, the PSC is turned on and the copy paper is conveyed. In this way, when ΔTC is positive, by scanning the optical unit and transporting the copy paper after the time ΔTC has elapsed, the center of the copy paper will be transferred to correspond to the center of the original.

FIG. 12 is a flowchart showing the processing procedure when performing shift copying.

First, calculate ΔTS at n90. This .DELTA.TS is determined by calculating the time corresponding to the shift distance input using the numeric keypad in step n33 of FIG. 9B. This time is determined by the above equation (2).

If the value of ΔTS is negative, the process from step n92 onward is performed, and if the value is 0 or more, the process is performed from step n92 onwards.
Perform processing after n100. These processes are the 11th
The only difference is the time waiting value in the case of centering copying shown in the figure.

FIG. 13 is a flowchart showing the process of step n50 in FIG. 9B.

First, in step n502, the size I of the image to be exposed on the photosensitive drum is determined by multiplying the document size D and the copying magnification m. At n503, this value is compared with the copy paper size S, and if it is less than the copy paper size S, at n504, the document size D is compared with the effective distance L0 that the document table can scan.

If the original size D is less than or equal to L0, it is possible to copy the original. If the original size D exceeds L0, copying is impossible, and the retrieval lamp is turned off at n505, and the magnification display is blinked at n506. On the other hand, when the size of the image on the photosensitive drum is larger than the size of the copy paper, the scanning distance of the document scanning means is expressed as (D+S/m)/2 as described above, and this value is
It is determined in n507 whether it is less than or equal to L0. L0
Since copying cannot be performed if the value exceeds , the ready lamp is turned off at n505 and n506, and the blinking display is made to blink.

Step n508 is to calculate the time TF required for scanning by the document scanning means when the size of the image on the photoconductor drum is less than the size of the copy paper, and step n510 is to find the time TF required for scanning by the document scanning means when the size of the image on the photoconductor drum exceeds the size of the copy paper. The purpose is to find the time required for scanning by the document scanning means in the case of the following. The time thus obtained is input into the memory MC, and then the ready lamp is turned on at n512.

The time TF is used in processing A, processing B, and processing D described above.

In the above embodiment, the timing of transporting the copy paper is controlled by predicting the time until the document scanning means reaches the leading edge position of the document. However, another method is to control the conveyance timing of the copy paper by predicting the time until the document scanning means reaches the leading edge position of the document. It is also possible to detect this, activate a timer, and transport the copy paper when the timer reaches a predetermined value.

<Effects of the Invention> As described above, according to the present invention, the scanning distance of the document scanning means can be set to the shortest distance according to the size of the copy paper, the size of the document, and the copy magnification, and the image relative to the center of the copy paper can be set to the shortest distance. can be copied in a short time.

In addition, when copying factors such as copy paper size, original size, and copying magnification are input or automatically detected, copying is enabled or disabled by determining whether the scanning distance of the original scanning means is within the valid range. The operator can be notified in advance.
Therefore, it is possible to check in advance for mistakes in the settings of each of the copy elements.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the acceleration time of the document scanning means at different copying magnifications, Fig. 2 is a diagram showing the relationship between the copying magnification and acceleration time, and Fig. 3 is the configuration of the optical system mobile copying machine. 4 is a diagram showing the scanning speed of the document scanning means and the signal of the home position switch, FIG. 5 is a diagram showing the relationship between the document and the image for each copying magnification, and FIGS. 6 and 7 are FIG. 8 is a block diagram of the control section of the copying apparatus of the present invention, and FIGS. 9A, 9B, and 13 are diagrams showing the relationship between the image, the copy paper, and the scanning distance of the document scanning means, and FIG. 9A, FIG. 9B, and FIG. 10 is a flowchart showing the processing procedure for normal copying, and FIG. 11 is a flowchart showing the processing procedure for centering copying.
2 each represents a flowchart showing the processing procedure of shift copying.

Claims (1)

[Scope of Claims] 1. A document scanning device consisting of an optical unit or a reciprocating device for a document table; a photoconductor drum that exposes an image by scanning the document; and a copy sheet conveyed to the photoconductor drum; In a copying device that transfers an image to the center of copy paper as the photosensitive drum rotates, the image size I (I =
means for conveying the copy paper at a timing when the center of the image size I is equal to or smaller than the copy paper size S (I
≦S), the document scanning distance by the document scanning means is set to a distance corresponding to the length D of the document in the scanning direction, and the image size I is larger than the copy paper size S (I>S). In this case, the document scanning distance by the document scanning means is 1/2 of the sum of the length D of the document in the scanning direction and the length S of the copy paper in the conveying direction divided by the copying magnification m. The distance corresponding to (D+
s/m)/2; and means for prohibiting copying when the set distance exceeds an effective scanning distance LO of the document scanning means determined by a magnification. copying equipment.