JPH0315185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a copying apparatus that performs copying by scanning a document at a constant speed with a document scanning device including an optical unit or a reciprocating device such as a document table.

<Summary of the Invention> The present invention is a copying apparatus which is equipped with an original scanning means consisting of a reciprocating means such as an optical unit or an original placing table, and whose scanning speed is controlled according to a copying magnification. In a device in which the acceleration time from the home position of the document scanning device to the reference position in the constant speed traveling section has a proportional relationship and can copy at the center of the copy paper, from the home position of the document scanning device to the leading edge of the document, for example. The acceleration time required for scanning to the position is calculated in advance from the information obtained from preliminary scanning, and the time required for the recording medium to move the distance from the image forming position to the transfer position from the conveyance means to the transfer position is determined during this acceleration time. Determine the timing of transporting the copy paper based on the time obtained by subtracting the transport time of the copy paper and adding the time required to transport the copy paper between the leading edge position of the copy paper and the leading edge position when copying to the center of the copy paper. This is how it was done.

<Prior Art and Its Disadvantages> Conventionally, when copying an original, the copying was performed at a position slightly shifted from the copying paper. However, in the conventional method, the timing of conveying the copy paper is determined within the range in which the document scanning device moves at a constant speed based on the point at which the document scanning device reaches the leading edge of the document. It was limited to about 10 mm.

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 which is a recording medium;
PSC is a paper start clutch, and the copy paper is temporarily stopped at this point and conveyed at a predetermined timing. In such a configuration, conventionally, a timer is activated from the time when the first mirror reaches P2, and after a predetermined time has elapsed, the PSC is controlled, and the exposure time, which is the image forming position of the photoreceptor drum 6, is controlled. Distance l1 from P4 to transfer position P5 and
The distance between PSC position P6 and transcription position P5 is l2
Then, l1-l2 is the maximum distance that can be shifted. For this reason, as mentioned above, it was only possible to shift by about 10 to 20 mm at most. Furthermore, if the document scanning means runs at a constant speed before exposing the leading edge of the document, a large distance must be taken from when the document scanning device starts until it exposes the leading edge of the document, which increases the size of the copying apparatus. There were flaws.

However, in recent years, the available copying magnification has expanded both in the enlargement and reduction directions, and for example, it is no longer possible to automatically transfer a reduced image to the center of the copy paper (centering). Ta.

<Object of the Invention> An object of the present invention is to provide a copying apparatus that eliminates the above-mentioned drawbacks and enables copying to be performed at the center of copy paper according to copy factors such as copy paper size, original size, and copy magnification. It's about doing.

<Structure of the Invention> (a) Principle The basic principle of the present invention is to determine the time required from the home position to reach a reference position such as the leading edge position of the original when scanning the original scanning means such as the optical unit. Therefore, it is possible to transport the copy paper before the document scanning means reaches a constant speed.

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. After starting the original scanning means, the number of pulses is counted and reaches n. The point in time becomes the reference position. In other words, Tm1 is the acceleration time for the original scanning means to reach the reference position from the home position when the copying magnification is the maximum, and Tm2 is the acceleration time for the original scanning means to reach the reference position from the home position when the copying magnification is the minimum. represents the acceleration time of

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 from the following equation.

Tm=Tm1+(Tm1−Tm2)×(m−m1)/
(m1-m2) During the acceleration time obtained in this way, the time 11/V0 for the recording medium to move the distance 11 from the image forming position (P4 in Figure 3) to the transfer position P5, and from the conveying means to the transfer position. Copy paper transport time l2/
The copy paper conveyance timing can be set based on the time obtained by subtracting V0 (l1-l2)/time obtained by adding V0. That is, if the time difference between the timing at which the document scanning means starts operating from the home position and the timing at which the copy sheet is conveyed is ΔT, it can be determined by the following equation.

ΔT=Tm+(l1-l2)/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.

This time relationship determines the copying position relative to the copy paper, so if you control the conveyance timing of the copy paper by adding or subtracting the time required to further shift the image to this time, you can shift the copy image. It can be performed.

For example, if the distance to be shifted is SH, the time required for copy paper to travel that distance is
SH/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), the original size (width in the scanning direction) is D, the copy paper size is S, and the copy magnification is m. Then, the distance from the leading edge of the copy paper to the leading edge of the image to be copied can be found as (S-m×D)/2. Therefore, the timing of conveying the copy paper can be determined by the following equation.

ΔTC=ΔT-(S-m×D)/2V0...(3) (b) Structure of the Invention The present invention provides means for constant speed scanning of an original scanning means consisting of a reciprocating means such as an optical unit or an original placing table. a copying apparatus which controls its scanning speed according to a copying magnification, wherein the copying magnification has a proportional relationship with an acceleration time from a home position of the document scanning means to a reference position in a constant speed traveling section; In the case where a copy can be made at the center of a copy sheet, the copy sheet is conveyed at a speed equal to the rotation of a recording medium rotated at a circumferential speed V0, and the image formed on the recording medium is transferred to the copy sheet. distance l2
Conveying means placed apart and copy paper size (length in the copy paper conveyance direction) S
and document size (length in the direction of movement of the document scanning means)
A copying element setting means for setting a copying element of D and a copying magnification m by inputting or automatically detecting the copying element, and copying from the leading edge of the copying paper determined from the copying element set by the copying element setting means. Distance to the tip of the power image (S-m×D)/2
Based on the circumferential velocity V0 of the recording medium, the copy paper feeding time (S-m×
D) Copy paper feeding time calculating means for calculating /2V0; and means for pre-scanning the document scanning means at a speed corresponding to at least two or more different copying magnifications m1 and m2 before copying exposure scanning; Means for measuring acceleration times Tm1 and Tm2 from the home position of the document scanning means to the reference position of the constant speed traveling section corresponding to the two or more copying magnifications m1 and m2 by the preliminary scanning; Based on the information of acceleration times Tm1 and Tm2 corresponding to two or more copying magnifications m1 and m2, acceleration time Tm corresponding to any copying magnification m1 = Tm1 +
means for calculating (Tm1-Tm2)×(m-m1)/(m1-m2); and a time l1 for the recording medium to move a distance l1 from the image forming position to the transfer position in the calculated acceleration time Tm. The time difference ΔT is the time obtained by subtracting the transport time l2/V0 of the copy paper from the transport means to the transfer position from /V0 (l1 − l2)/VO, and the time difference ΔT and the copy paper transport time calculation means are calculated as follows: The time ΔTC = ΔT-(S-m ×D)/2V0 is calculated,
The present invention is characterized by comprising means for causing the conveyance means to start conveying the copy paper after measuring the calculated time ΔTC from the timing at which the document scanning means starts operating from a home position.

<Embodiment> 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 key is used to instruct 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, when the power of the copying machine is turned on, the memory is cleared in step n10 (hereinafter step numbers are simply indicated by their numbers), the optical unit is returned to the home position in n11, and a counter indicating that position is set. Initialize (MM stands for 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 copying magnification, and scanning by the document scanning means is performed based on this data. That is, first, at n13, the motor that drives the optical unit is turned on, and at n14, the motor that drives the optical unit is turned on.
Reset and start the timer TM at . n1
5 is for determining whether the value of the counter C has reached a predetermined number n. n16 is for determining whether or not the encode pulse EP shown in Fig. 1 has occurred, and if EP has occurred, n
At step 17, the counter is incremented. That is, through steps n15 to n17, counting is performed until the number of encode pulses EP reaches n. At step n18, it is determined whether the flag F1 is in the set state. Initially F1 is in a reset state. For this purpose, the flag F1 is first set at n19, and at n20, the value of the timer TM, that is, 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. Step n21 is a process for confirming that the optical unit has reached a constant speed. n24 is for waiting time until the optical unit drive system stabilizes.
Thereafter, the optical unit is returned to the home position at steps n25 and n26.

n27 is for determining flag F2,
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 flag F1 is already set at this point, n
This is determined in step 18, and the timer value is stored in the memory MB in step n22. Flag F2 at n23
This is determined at n27 by setting , 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. The average acceleration time at copying magnification m2 is determined as Tm2.

FIG. 4 shows a preliminary scanning speed pattern of the original scanning means (optical unit). In the figure, V1 is the document speed at the copying magnification m1, and V2
represents the scanning speed at the copying magnification m2, and Vr represents the speed when the optical unit returns.
Note that KPS 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 in step n30, and the initial settings of each part of the copying mechanism in the copying apparatus are performed in step n31. Thereafter, at n32, a ready lamp indicating a copy ready state is turned on. n33 is the original size D, copy magnification m, copy paper size S,
Read inputs such as centering specification CNT and shift specification. Each of these data can be input from the keyboard or automatically detected. Based on these read data, n50 performs processing to determine whether copying is possible and the time required for scanning by the document scanning means.
(This process will be explained in FIG. 13). n34 determines whether the print switch has been operated, and if the print switch has been operated, n35
The ready lamp is turned off at n36, and the paper feed roller (paper feed solenoid) is driven at n36.
At n37, ΔT is calculated. This value is calculated using the formula (1) above.
Perform calculations based on. 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, at n60, the state of the paper detection switch MS1 is determined. 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 it is in contact with the copy paper PSC, n61 is detected.
The scanning of the optical unit is started at n62, and the copy lamp is turned on at n62. Thereafter, in step n63, the process waits for the time ΔT already determined. After the time ΔT has elapsed, the PSC is turned on at n64. That is, the copy paper is conveyed at this timing. Step n65 is a process in which an image is transferred to the transported copy paper and the paper is finally ejected to a paper ejection tray. n66
is to judge whether all copies have been completed for the number of copies to be made; if not, n
Drive the paper feed roller (PFS in Figure 3) at 37, and
The process returns to 60 and the same process is performed. When all the copying processes are completed, the process returns to step n33 in FIG. 9B. 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, at n70, ΔTC is calculated. This ΔTC
is determined by the calculation of equation (3) above. If the value is negative, n72 first turns on the paper detection switch MS1.
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 step n74, the CPU waits for the already calculated time ΔTC, and after that time has elapsed, scanning of the optical unit is started at step n75, and the copy lamp is turned on at step n76. Step n77 is a process for transferring an image onto the transported copy paper and finally ejecting the paper to a paper ejection tray. n78 and n79 are the first
As in the case of Fig. 0, it is determined whether or not the number of copies to be made has been completed, and paper feeding processing for the next copy is performed.

In this way, when ΔTC is negative, the image can be transferred to the center of the copy paper by scanning the optical unit after ΔTC (absolute value) has elapsed by transporting the copy paper.

If ΔTC is 0 or more, first determine whether the copy paper is in contact with the PSC at n80, and then
Start scanning the optical unit at n8.
Turn on the copy lamp at step 2. After that, n83 waits for ΔTC, and after ΔTC has elapsed, n84
Turn on the PSC and transport the copy paper. In this way, when ΔTC is positive, by scanning the optical unit and transporting the copy paper after the lapse of the time ΔTC, 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, ΔTS is determined at n90. This ΔTS is obtained 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, step n92
The subsequent processing is performed, and if the value is 0 or more, the processing from step n100 onwards is performed. These processes are the first
The only difference is the time waiting value in the case of centering copying shown in FIG.

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, it is c.
The image size is −c′.

FIGS. 6 and 7 show the relationship between such an image and the scanning distance of copy paper and original scanning means. Image size 1 as shown in Figure 6
If S is smaller than the size S of the copy paper, the optical unit can transfer the image to the center of the copy paper by scanning a distance corresponding to the size of the image, that is, a distance equal to the original size D. 7th
As shown in the figure, when the image on the photoconductor drum is larger than the copy paper, the distance corresponding to 1/2, that is, D/2, is required to expose the first half of the image (the left half in the figure) onto the photoconductor drum. scanning of the optical unit is required. 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 S/2 m.
Therefore, the operating distance of the entire optical unit is (D+
S/m)/2.

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

First, in step n501, the size 1 of the image to be exposed on the photosensitive drum is determined by multiplying the document size D by the copying magnification m. In n502, this value is compared with the copy paper size S, and the copy paper size S is determined.
If it is less than that, the document size D is compared with the effective scanning distance L0 of the document table in n503.
As shown in FIG. 3, this distance L0 is determined by the distance between the third mirror and the zoom lens and the copying magnification. If the original size D is less than or equal to L0, it is possible to copy the original. Original size D
If the size exceeds L0, copying is impossible, and the ready lamp is turned off at n505 and n506
The display for magnification display blinks. On the other hand, if 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 less than or equal to L0. Whether n507
It is determined by Since copying cannot be performed if the value exceeds L0, the ready lamp is also turned off at steps n505 and n506, and the blinking display is made to blink.

Step n508 is for calculating the time TF required for scanning by the document scanning means when the size of the image on the photosensitive drum is less than the copy paper size.
10 is for determining the time required for scanning by the document scanning means when the size of the image on the photosensitive drum exceeds the size of the copy paper. Input the time obtained in this way into the memory MC, and then
Turn on the ready lamp.

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

<Effects of the Invention> As described above, according to the present invention, the acceleration time required for scanning from the home position of the document scanning means to the reference position such as the leading edge position of the document is predicted in advance, and the document is copied to the center of the copy sheet. By predetermining the conveyance timing of the copy paper in each case, it is possible to perform copying at the center of the copy paper even if each copying element such as the copy paper size, original size, and copy magnification is arbitrarily set.

Further, since the preliminary scan is only performed when the power is turned on, it does not interfere with normal copying operations. Further, by performing a preliminary scan a plurality of times at different copying magnifications and finding the average value of the acceleration time of the original scanning means such as an optical unit, the acceleration time at any copying magnification can be determined more accurately.

[Brief explanation of the drawing]

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 copying apparatus comprising means for constant-speed scanning of an original scanning means consisting of a reciprocating means such as an optical unit or an original placing table, and controlling the scanning speed according to a copying magnification. There is a proportional relationship between the magnification and the acceleration time from the home position of the document scanning means to the reference position of the constant speed traveling section,
For those capable of copying at the center of the copy paper, the copy paper is rotated at a circumferential speed of V0, and the image is transported at a speed equal to the rotation of the recording medium, from the position where the image formed on the recording medium is transferred to the copy paper. distance l2
Conveying means placed apart and copy paper size (length in the copy paper conveyance direction) S
and document size (length in the direction of movement of the document scanning means)
A copying element setting means for setting a copying element of D and a copying magnification m by inputting or automatically detecting the copying element, and copying from the leading edge of the copying paper determined from the copying element set by the copying element setting means. Distance to the tip of the power image (S-m×D)/2
Based on the circumferential velocity V0 of the recording medium, the copy paper feeding time (S-m×
D) Copy paper feeding time calculating means for calculating /2V0; and means for pre-scanning the document scanning means at a speed corresponding to at least two or more different copying magnifications m1 and m2 before copying exposure scanning; Means for measuring acceleration times Tm1 and Tm2 from the home position of the document scanning means to the reference position of the constant speed traveling section corresponding to the two or more copying magnifications m1 and m2 by the preliminary scanning; Based on the information of acceleration times Tm1 and Tm2 corresponding to two or more copying magnifications m1 and m2, acceleration time Tm corresponding to any copying magnification m=Tm1+
means for calculating (Tm1-Tm2)×(m-m1)/(m1-m2); and a time l1 for the recording medium to move a distance l1 from the image forming position to the transfer position in the calculated acceleration time Tm. The time difference ΔT is the time obtained by subtracting the transport time l2/V0 of the copy paper from the transport means to the transfer position from /V0 and adding (l1 − l2)/V0, and the time difference ΔT and the copy paper feeding time calculation means are calculated as follows: The time ΔTC = ΔT-(S-m ×D)/2VD0, and after measuring the calculated time ΔTC from the timing when the original scanning means starts operating from the home position, the transporting means starts transporting the copy paper. A copying device characterized by: