JPH0727169B2 - How to set the run-up distance for variable magnification copiers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of setting the above-mentioned running distance of a variable-magnification copying machine, which changes the running distance of a document scanner according to a copy magnification, in a storage device.

(B) Conventional Technology In a copying machine that reads a document image by moving a document scanner, the reading speed must be constant in order to eliminate distortion in the scanning direction of the copied image. For this reason, an approach distance is provided to accelerate the document scanner to a predetermined reading speed before the exposure operation is started. By the way, in a variable-magnification copying machine capable of performing enlargement or reduction copying, enlargement or reduction is performed by changing the document scanning distance with respect to the image forming length. That is, if the original scan distance is increased with respect to the image forming length, the image of the original is reduced and copied, and if the original scan distance is reduced with respect to the image forming length, the original is enlarged and copied. By the way, since the image forming length (peripheral speed of the photoconductor) is constant at any copying magnification, the original scanning speed increases as the copying magnification decreases, and a long-distance run-up is required.

Therefore, at the time of reduction copying, the start position of the document scanner is set so that a long approach distance can be obtained to the leading end of the document, which is the exposure start position. On the other hand, the moving speed of the manuscript scanner is not so high during the same size copying and the enlarging copying, so that the run-up distance is short and the start position of the manuscript scanner is set at a position closer to the leading edge of the document than in the reduction copying.

As described above, in order to achieve both stable original scanning speed during reduction copying and improvement in copying speed during equal-magnification / enlargement copying, a variable-magnification copying machine has conventionally been proposed in which a plurality of run-up distances are set according to the copying magnification. (Japanese Patent Application Sho 62-12
No. 4468).

(C) Problems to be Solved by the Invention By the way, in the variable-magnification copying machine as described above, a home position sensor is attached near the original scanner start position (home position) corresponding to each copying magnification, and the original scanner is moved. A rotary encoder that measures the distance is provided, and the exposure operation starts when the original scanner passes a predetermined home position sensor at the start of copying and then measures the movement of the approach distance set for that home position sensor. Has been

Conventionally, the distance data between the home position sensor and the leading edge of the original document, which is the exposure operation start position, is set by a clerk by a simulation at the time of production (the distance data should be stored in the control unit of the variable magnification copying machine. The same), and in the variable magnification copying machine having a plurality of home position sensors as described above, this work was performed for each home position sensor.

For this reason, personnel work in the production stage increases, which causes the production cost to rise, and when the distance between each home position sensor and the leading edge of the document deviates due to aging due to use, all data is set. There was a problem that had to be corrected.

The present invention has been made in view of such problems,
An object of the present invention is to provide a method for setting an approach distance of a variable magnification copying machine, which solves the above-mentioned problems by setting the approach distance of one of the plurality of home position sensors as a reference approach distance.

(D) Means for Solving Problems The present invention has moving distance measuring means for measuring the moving distance of the document scanner, and a plurality of home position sensors for detecting passage of the document scanner are provided in accordance with the copy magnification. An approach distance, which is the distance from each home position sensor to the leading edge of the document, is set for each home position sensor, and at the start of copying, the document scanner passes through the home position sensor corresponding to the copy magnification at that time, and then the home position sensor. A method for setting an approach distance for each home position sensor in a variable magnification copier that starts an exposure operation when the movement of the approach distance set in a position sensor is measured by the moving distance measuring means, One of the multiple home position sensors The mileage is stored in advance as a reference mileage, and the mileage of the other home position sensor is set to the other home position sensor and the one home position sensor each time the main switch of the copying machine is turned on. It is characterized in that the distance is measured by the moving distance measuring means by moving the document scanner during this time, and then the measured distance is added to the reference approach distance.

(E) Action The approach distance setting method for the variable magnification copying machine of the present invention is the distance between the home position sensor provided in the vicinity of the start position of the original scanner and the leading edge of the original at the same size / enlarged copy and reduced copy. When setting the (running distance), the running distance from one of the home position sensors (generally for normal magnification / enlarged copying) is selected by the data input method using the simulation function that has been conventionally performed. Is set. Next, the distance between the one home position sensor and another home position sensor is measured at the first operation of the variable magnification copying machine or each time the main switch is turned on. This distance is added to the reference approach distance to set the approach distances of other home position sensors. If the one home position sensor is farther from the leading edge of the document than the other home position sensors, the subtraction is performed. However, if the distance is directional, all the processes can be performed as addition. it can.

As a result, the simulation work in the production stage can be completed only once, the production cost can be reduced, and the approach distances for other home position sensors can be set each time the main switch is turned on. It is possible to set the run distance according to the secular change, and the maintenance of the staff members only needs to be performed for the standard run distance.

(F) Embodiment FIG. 2 is a schematic structural diagram of a variable magnification copying machine which is an embodiment of the present invention. In the figure, reference numeral 1 is a main body of a copying machine, on which an original table 2 is installed, and a paper feed cassette is provided on the right side.
3, 4 and a paper discharge tray 5 is installed on the left side. Further, a photoconductor drum 6 which rotates in the direction of the arrow is arranged at a substantially central portion of the copying machine main body 1, and a charging device 7, a discharging lamp 26, a developing device 8, a transfer device 9, a peeling device 10, a discharging device 11 are provided around the photosensitive drum 6. Blade 12a
A waste toner collecting unit 12 including is disposed. The optical system for forming the image of the original on the exposure point a of the photosensitive drum 6 includes four reflection mirrors 13 to 16 and a lens 17, and the scanner (original scanner) is a mirror 13 to 15, a light source for illuminating the original ( (Not shown) and the light blocking plate 18. The shading plate 18 can cross the home position sensors 19a, 19b, 19c arranged on the upper left side of the copying machine body 1.
When 8 crosses the home position sensor, the counter described later starts.

The scanner is driven by a motor, and a rotary encoder (not shown) is attached to the rotary shaft of the motor. The rotary encoder generates one pulse each time the scanner advances a certain distance. The counter counts the pulses from this rotary encoder to know the moving distance of the scanner. Point A in the figure indicates the position of the leading edge of the document. The moving speed of the scanner is NF here, and the photosensitive drum 6
The peripheral speed of is set to ND. The magnification can be changed by adjusting the zoom of the lens 17, the moving speed NF of the scanner and the peripheral speed of the photosensitive drum 6.
This is done by changing the speed ratio with ND. If the magnification is 1 ×, ND / NF = 1. ND / NF when the magnification is 0.64 times the reduction
= 0.64, which is 1.41 times the expansion, ND / NF = 1.41. Since the peripheral speed ND of the photosensitive drum 6 is normally maintained at a constant speed, the moving speed NF of the scanner is set to obtain the above speed ratio.
To change. That is, when 0.64 times, NF = ND
It becomes /0.64, and when it is 1.41 times, it becomes NF = ND / 1.41. The transfer paper fed from the paper feed cassette 3 or 4 by the paper feed roller 20 or 21 is a paper stopper roller (hereinafter
It is called PS Roller) 22 and stops once. The switch 23 detects that the leading edge of the transfer paper has reached the position of the PS roller 22. That is, when the switch 23 detects that the leading edge of the transfer paper has reached the position of the PS roller 22, the paper feeding by the paper feeding roller 20 or 21 is stopped.

FIG. 3 is a schematic block diagram of a control unit of the copying machine. In the variable magnification copying machine of this embodiment, the master CPU controls the entire copying machine.
Boat 30 and slave CP connected to it by communication line 32
Perform with U board 31. The slave CPU board 31 controls a mirror motor (BLM) 29 for driving the scanner, a solenoid PSC24 for driving the PS roller 22, and a lens driving motor (STM) 25, and is attached to the rotation axis of the mirror motor 29. It receives signals from various sensors for motors (including rotary encoders) and signals from various sensors such as the home position sensors 19a, 19b, 19c of the scanner and the sensor for detecting the home position sensor of the lens 17. Numeral 26 is a static elimination lamp for trimming, which is composed of an LED array consisting of n LEDs as shown in FIG. Each LED is turned on / off by a signal output from the master CPU board 30. An operation board 27 is used to set the copy magnification and trimming area.

Here, the home position sensors 19a, 19b, 19c are provided in this order from the position close to the document leading edge position A, and the home position sensor 19a is provided at the home position at the same magnification or magnified copying.
b and 19c are provided at the home position for reduction copying of 1.0 to 0.8 times and 0.8 times or less, respectively. The home position sensor is turned on when the scanner is on the return side of the scanner and turned off when it is on the scan side. The distances (running distances) between these home position sensors 19a, 19b, 19c and the document leading edge position A are calculated as (PSC-
A), (PSC-A) ', and (PSC-A) ". Of these, (PSC-A) is input by a clerk using a simulation function during production. That is, the home position sensor 19a is the present invention. (PSC-A) is the reference approach distance of the present invention. Hereinafter, the home position sensor 19a is referred to as the reference home position sensor. On the other hand, (PSC-A) 'and (P
SC-A) "is automatically set by the operation shown in the flowchart of FIG. 1 when the main switch of the device is turned on.

1 is a flow chart showing the automatic setting operation of the above (PSC-A) 'and (PSC-A) ". This operation is performed every time the main switch of the variable magnification copying machine is turned on. First, at n30, the position of the scanner is judged and the scanner is moved to the left end, then the counters C3 and C4 are cleared (n
31), start the scanner in the feed direction (rightward in the figure) (n32). At the same time, the rotary encoder starts to operate, and a count pulse is input each time it moves a predetermined distance. When a count pulse is input, n33 is judged.
The operation proceeds to the steps below 35, and the third home position sensor 19
c signal output BLP1 and second home position sensor 1
It is determined whether the 9b signal output BLP2 is off (n3
5, n37). Counts up counter C3 when BLP1 is off and counters when BLP2 is off.
Count up C4 (n36, n38). This operation is repeated each time a count pulse is input.When the signal output MHP of the reference home position sensor 19a turns off n34 to n
Go to 39 and below. At n39, the value of the counter C3 is read and the reference approach distance (PSC-A) is added to this data (PSC
-A) "is calculated, and in n40, the value of the counter C4 is similarly read to calculate (PSC-A) '. These data are stored in the memory of the slave CPU board 31 and the main switch is turned on. It is used as the run-up distance during short-duration copying.

In the above operation, the scanner is always moved to the left end and the distance is measured while moving in the scanning direction during the copying operation, so that it is possible to measure with the same sensor start-up as during the copying operation. It is possible to eliminate the measurement error and the error between the copying operation and the measurement.

Further, in this variable power copying machine, various timings of the copying process are performed based on the count of (PSC-A) or the like. The trimming copying operation will be described below.

By operating the operation board 27, a region to be trimmed can be designated. For example, in FIG. 5, if it is desired to erase only the hatched portion, s-t-u-
Enter the position of v. In the copy cycle, the original image formed on the photoconductor is the LED (Pa-Pb) at the corresponding position of the static elimination lamp 26 corresponding to st in the drum axis direction of the photoconductor drum 6 as shown in FIG. ) Is lit to remove the charge from that part. Transfer paper transport direction s
-U, t-v is the direction of rotation of the photosensitive drum, so Pa- of the static elimination lamp is based on the position data of the scanner.
The timing for turning on and off the Pb LED is determined.

FIG. 6 is a time chart showing the control contents of the slave CPU board 31. First, a normal copying operation at a copying magnification equal to or larger than 1 × will be described.

When a normal document is set on the document table and a copy button (not shown) is pressed, the document scanner starts moving from the stop position. The moving speed at this time is determined by the copy magnification. Slave CPU board 31 is the master C for setting the moving speed NF
This is done by receiving the data of the set magnification from the PU board 30. When the slave CPU board 31 performs this calculation to determine the moving speed NF and starts driving the mirror motor 29 to move the scanner to the right, the light shielding plate 18 crosses the reference home position sensor 19a at a certain point. T2 at this point
And the starting time of the scanner is t1. Slave CPU
The board 31 has a counter and a timer inside it.
At time t2, the counter starts counting pulses input from the rotary encoder. CPU board 31
Determines that the scanner has reached the document leading edge position A when the number corresponding to (PSC-A) is counted. The counter in this case is a subtraction counter, the count value corresponding to (PSC-A) is input in advance, and the count value is decremented by 1 each time one pulse is received from the rotary encoder. A count-up signal is generated when the count value reaches 0, and it is determined that the scanner has reached the document leading edge position A based on this count-up signal. At this time, the image at the leading end position of the document is exposed at the exposure point a of the photosensitive drum 6.

When the count-up signal is generated, the slave CP continues.
The timer in the U board 31 starts. This timer is the time required for the image at exposure point A to reach point b (see FIG. 2) on the transfer section at speed ND, and the time for the leading edge of the transfer paper to reach point b from the position of PS roller 22. Is for adjusting. From the point a to the image b on the photosensitive drum, the timer time
From the time it takes to reach the point, the tip of the transfer paper is the PS roller.
It is the value obtained by subtracting the time from the position 22 to the point b. This timer time is (PSC-B). Slave C
When the PU board 31 starts this timer and detects a time-up signal after the time (PSC-B) has elapsed, the clutch PSC24 of the PS roller is turned on. By this control, the leading edge of the image formed on the photosensitive drum at the point b and the leading edge of the transfer paper can be matched. When the set magnification changes, the moving speed NF of the scanner changes, but since the pulse formed by the rotary encoder is generated once every time the scanner moves a certain distance, the document leading edge is irrelevant regardless of the moving speed NF. A count-up signal is always generated when the scanner reaches the position A.

Next, the operation when the trimming shown in FIG. 5 is performed will be described. As shown in FIG. 2, the position on the drum immediately below the static elimination lamp is c, and the distance between a and c is x0. The position of the scanner (the value of the counter indicating the position) of the scanner when the leading edge of the document image on the photosensitive drum is at point c is A0 in FIG. The number of pulses l0 in the meantime is calculated by the following equation.

l0 = x0 / Δl where Δl represents the distance around the photosensitive drum for one pulse of the rotary encoder. The above equation is for a case where the copy magnification is equal (the peripheral speed of the photoconductor drum and the moving speed of the scanner are equal), and the following formula is used as a general formula for variable magnification.

l0 = x0 / (Δl · Z) where Z represents the copy magnification.

Next, if the value of the counter when the scanner reaches the position corresponding to the st line shown in FIG. 5 is A1 and the value of the counter when reaching the uv line is A2, A1 = A0 + x1 / Δl A2 = A0 + x2 / Δl.

Also, A0 = (PSC-A) -l0 = (PSC-A) -x0 / (Δl · Z).

Therefore, A1 and A2 can be expressed by the following equation.

A1 = (PSC-A) -x0 / (Δl · Z) + x1 / Δl A2 = (PSC-A) −x0 / (Δl · Z) + x2 / Δl If expressed as a general formula, A = (PSC-A)-( x0 / Δl) (1 / Z) + x / Δl. Here, x0 / Δl and Δl are constants.

Based on the above relationship, the on / off timing of the static elimination lamp (BL) is set to the copy paper leading edge adjustment value, that is, (PSC-A) data, the copy magnification Z, and the data indicating the trimming location (x
1, x2). That is, as shown in FIG. 6, the count value A1 corresponds to the count number from A0 to x1 / Δl, or A2 corresponds to the count number from A0 to x2 / Δl, and has no relation to the copy magnification.

As described above, the timing A0 corresponding to the difference of the timing difference (l0) required for the photosensitive drum to move from the charge eliminating lamp to the exposure point with respect to the value corresponding to the document leading edge position (the point at which the count-up signal is generated) is displayed by the counter. The timing control for driving the static elimination lamp is performed with reference to.

If you want to make a copy at 1x or more magnification as above,
The pulse of the rotary encoder is counted after the signal output MHP of the reference home position sensor 19a is turned off,
When the value reaches a value calculated in advance, lighting control of the static elimination lamp is performed.

Next, the timing control when performing reduction copying will be described. As described above, since the moving speed of the scanner is high at the time of reduction copying, a long approach distance is required. Further, when performing trimming for reduction, the approach distance is required for the following reasons.

As shown in FIG. 6, the counter operation is started from the time t2 when the MHP changes from the ON state to the OFF state, but the time t3 when the position of the photosensitive member where the image of the leading edge of the document is exposed is point c is naturally
It must be t3> t2. That is, in FIG. 4, ΔT34 <ΔT24, if this is replaced by the pulse number, then l0 <
(PSC-A), or in terms of distance, l0 · Δl <(PSC-A) · Δl l0 = X0 / (Δl · Z), X0 / Z <LN (1) where LN is the original scanner Is the distance traveled after the MHP is turned off until the image at the leading edge of the document reaches the exposure point a of the photosensitive drum. From the formula (1), in the case of reduction copying, the LN distance is made longer as the copying magnification becomes smaller. Specifically, when the copy magnification is less than 0.8, the home position sensor 19c shown in FIG. 2 is used, and when the copy magnification is 0.8 or more and less than 1.0, the home position sensor 19b is used. FIG. 7 shows the output timing of the above three home position sensors and the lighting timing of the static elimination lamp. For example, when the copy magnification is 0.8, the output signal BLP2 of the home position sensor 19b is used, and the original scanner reaches the leading edge position of the original after a predetermined count number (PSC-A) 'from the time when this signal is turned off. In addition, the pulse l
The lighting timing of the static elimination lamp is determined with reference to the timing A0 'before 0'.

FIG. 8 shows the processing procedure of the slave CPU that performs such timing control. First, determine the copy magnification range and set the counter value that indicates the on / off timing of the static elimination lamp to A
Calculate as 1, A2 (n2, n4, n5). Then, the original scanner is started and the state of the home position sensor corresponding to the range of the copy magnification is determined (n8, n10, n1
1). For example, when the copying magnification is less than 0.8, the state of the signal BLP1 is discriminated, the state is waited until it is turned off, and when it is turned off, the counter C1 starts counting pulses (n13). If the signal MHP is turned off during this counting, the counter C2 is also counted at the same time (n14). C1
When the value of reaches the pre-determined value A1, the static elimination lamp is turned on (n16), and when it reaches A2, the static elimination lamp is turned off (n1
8). When the value of C2 reaches (PSC-A) during counting, that is, when the scanner reaches the leading edge of the document, the paper start clutch P
Start the timer for turning on the SC (n19 → n2
0).

In this way, during reduction copying, the on / off timing of the static elimination lamp is controlled based on the signal of BLP1 or BLP2, and the conveyance start control of the paper is performed based on the signal MHP.

(G) Effect of the Invention As described above, according to the present invention, even if the home position sensor is provided according to the copy magnification, if one of the run distances is set in advance, the run of another home position sensor can be performed. The distance can be calculated by measuring the distance to the one home position sensor using the moving distance measuring means and then adding this distance to the reference approach distance. That is, such an operation can be performed by the copying machine itself, and the running distance can be automatically set. Further, since such automatic setting can be performed when the power of the device is turned on, the approaching distance can be calculated according to the secular change of the device, and the maintenance can be facilitated.

[Brief description of drawings]

FIG. 1 is a flow chart showing an approaching distance setting operation of a variable magnification copying machine to which an approaching distance setting method according to an embodiment of the present invention is applied. FIG. 2 is a schematic configuration diagram of the variable magnification copying machine. FIG. 4 is a block diagram of a control unit of the variable power copying machine, FIG. 4 is an enlarged view of a photosensitive drum and a charge eliminating lamp of the variable power copying machine, and FIG. 5 is an original copied by the variable power copying machine and its trimming area. FIG. 6, FIG. 6 and FIG. 7 are timing charts of the control unit when copying the original shown in FIG. 5, FIG. 6 is a timing chart at the time of copying at the same size, and FIG. 3 is a timing chart in FIG. FIG. 8 is a flow chart showing the operation of the control unit at the start of copying. 19a, 19b, 19c …… Home position sensor.

Claims (1)

[Claims] 1. A moving distance measuring means for measuring a moving distance of a document scanner is provided, and a plurality of home position sensors for detecting passage of the document scanner are provided in accordance with a copying magnification. The approach distance, which is the distance between them, is set for each home position sensor, and after the original scanner passes the home position sensor corresponding to the copy magnification at that time at the start of copying, the approach distance set for that home position sensor is set. A method for setting an approach distance for each home position sensor in a variable magnification copier that starts an exposure operation when the movement is measured by the movement distance measuring means, wherein one home of the plurality of home position sensors is set. The approach distance of the position sensor is recorded in advance as the reference approach distance. It should be noted that the run-up distance of the other home position sensor is the distance between the other home position sensor and the one home position sensor each time the main switch of the copying machine is turned on. Is moved and measured by the moving distance measuring means, and the measured distance is added to the reference running distance to set the running distance.