JPS6265061A - Copying machine with trimming function - Google Patents

Abstract

PURPOSE:To attain a proper trimming at optional magnifications by controlling the drive timing of a destaticizing lamp with a timing difference necessary for a photosensitive body to move from the destaticizing lamp to an exposure point, and vice versa, as a reference. CONSTITUTION:An optical system forming the image of an original at the exposure point (a) of a photosensitive drum 6 includes reflection mirrors 13-16 and a lens 17, and a scanner is constructed with the mirrors 13-15, a light source irradiating the original and a light shielding plate 18. A counter starts when said plate 18 crosses a mirror home position sensor 19. A motor drives the scanner, and a rotary encoder fitted on the rotary spindle of the motor generates pulses whenever the scanner advances a certain distance. Using the timing equivalent to the timing difference necessary for the drum 6 to move from the destaticizing lamp 26 to the exposure point (b) as a reference with respect to a value corresponding to an original tip position, the counter controls the timing when the lamp 26 is driven, thereby attaining the proper timing at any manifications.

Description

[Detailed Description of the Invention] Technical Field> The present invention provides timing control for trimming a desired area of an image formed on a photoreceptor using a static elimination lamp in a zoom copying machine in which magnification can be set steplessly. The present invention relates to a copying machine having a distinctive trimming function.

<Summary of the Invention> The present invention provides a pulse forming means for forming a number of pulses corresponding to the moving distance of the document scanner, and measures and sets the moving distance of the document scanner from the home position by forming the pulses. Even if the scanner movement speed changes depending on the magnification, the predetermined position from the leading edge of the document can always be accurately determined.B) The static elimination lamp irradiates the predetermined area of the document image with accurate timing. make it possible. As a result, accurate 1-rimming can be performed, and it is substantially unnecessary to adjust the lighting timing of the static elimination lamp with respect to the leading edge of the document.

<Prior art and its drawbacks> When trimming an original image formed on a photoreceptor by irradiating it with a static elimination lamp, it is necessary to determine the irradiation position in the scanning direction of the original by controlling the lighting timing of the static elimination lamp. .

In conventional copying machines, the position of the leading edge of the document on the photoreceptor,
It was necessary to adjust the lighting timing of the static elimination lamp with respect to this position, and it was also necessary to make similar adjustments according to each copying magnification. For example, by storing the scanner movement time from the home position to the leading edge position of the document according to the set magnification in advance in memory, and using the time data and timer stored in this memory, the leading edge of the document can be positioned according to the set magnification. I was trying to detect it. However, with this method, zoom copying machines that can set the magnification steplessly require an extremely large amount of data to be stored in memory, and the adjustment is also extremely complex, so this method is not practical. It was impossible to do so.

<Objective of the Invention> An object of the present invention is to trim a predetermined area of a document image at an accurate position with a static elimination lamp at any copying magnification, and to adjust the lighting timing of the static elimination lamp relative to the leading edge of the document. It is an object of the present invention to provide a copying machine having a trimming function that is substantially unnecessary.

<Configuration and Effects of the Invention> To summarize, the present invention provides a home position detection sensor for detecting the home position of a document scanner configured as follows, and also includes a home position detection sensor that detects the home position of a document scanner configured as follows. A pulse forming means is provided for forming the pulse. This pulse forming means is formed by a rotary encoder, for example, and forms a number of pulses corresponding to the distance traveled by the scanner, regardless of the speed of movement of the scanner.

A counter is provided that starts counting the pulses formed by the pulse forming means from when the scanner passes the home position. This counter allows us to know the distance the scanner moves from its home position.

It also includes a static elimination lamp that trims a desired area of the original image on the photoreceptor. This static elimination lamp is composed of, for example, an LED array arranged in a straight line in the width direction of the photoreceptor, and trimming of the copy paper in the width direction is performed by lighting the LED array.
means for determining the timing difference required for the photoconductor to move from the static elimination lamp to the exposure point and from the exposure point to the static elimination lamp when the lamp is not lit; and the counter calculates the timing difference from a value corresponding to the document leading edge position. The present invention is characterized in that a control means is provided for controlling the timing of driving the static elimination lamp based on the timing corresponding to .

By configuring as shown below, the above timing difference is temporarily determined by the distance between the static elimination lamp and the exposure point, the moving speed of the photoreceptor, and the copying magnification. Therefore, the timing difference is determined according to the copying magnification. The pulse counter is started when the scanner passes the home position, and the static elimination lamp is turned on when the counter value changes from the value corresponding to the leading edge position of the document to the value corresponding to the timing difference. The driving timing can be controlled. As a result, accurate trimming can be performed regardless of the copying magnification, and furthermore, it is not necessary to adjust the lighting timing of the static elimination lamp with respect to the leading edge of the document.

<Example> (Explanation of al configuration) FIG. 2 is a schematic structural diagram of a zoom copying machine which is an example of the present invention.

In the figure, 1 is the main body of the copying machine, and there is a document table 2 on the top of this main body.
A paper feeding power center 3.4 is installed on the right side, and a paper discharge tray 5 is installed on the left side. Furthermore, approximately in the center of the copying machine main body l is a photosensitive drum 6 that rotates in the special training direction.
is placed around it, and a 1st charger 7. is placed around it. Static elimination lamp 2
6. Developing device 8, transfer device 9. Peeler 10. Static eliminator 1). A waste toner collection section 12 including a blade 12a is arranged. The optical system for focusing the image of the original on the exposure point a of the photosensitive drum 6 includes four reflecting mirrors 13 to 16 and a lens 17. ) and a light shielding plate 18. The light shielding plate 18 can cross a mirror home position sensor (hereinafter referred to as MHP sensor) 19 located on the upper left side of the copying machine main body 1, and this light shielding plate 18 can cross the mirror home position sensor (hereinafter referred to as MHP sensor)
[When the P sensor is crossed, a counter described later starts. The scanner is driven by a motor, and a rotary encoder (not shown) is attached to the rotating shaft of the motor. The rotary encoder generates one pulse each time the scanner advances a certain distance. The control unit counts the pulses from this rotary encoder and knows the distance traveled by the scanner. Point A in the figure indicates the leading edge position of the document.

Here, the moving speed of the scanner is set to NF, and the circumferential speed of the photosensitive drum 6 is set to NO. The magnification is changed by changing the speed ratio between the moving speed NF of the scanner and the circumferential speed ND of the photosensitive drum 6. If the magnification is the same, N
D/NF=1. N when the magnification is 0.64 times the reduction
D /N F = Ol, 64, which is 1.41 for expansion.
If it is double, ND /NF = 1.41. Since the circumferential speed ND of the photosensitive drum 6 is normally kept at a constant speed, the speed NF of the gap is changed to obtain the above speed ratio. After all, when it is 0.64 times, NF −N O10,
64, and when it is 1.41 times, NF=ND /1.4
It becomes 1. From paper feed cassette 3 or 4 to paper feed roller 2
The transfer paper fed by 0 or 21 is temporarily stopped at the position of a paper stop roller (hereinafter referred to as PS roller) 22. The switch 23 detects that the leading edge of the transfer paper has reached the position of the PS roller 22. That is, when this switch 23 detects that the leading edge of the transfer paper has reached the position of the PS roller 22, the paper feed roller 20 or 2
Stop paper feeding according to step 1.

FIG. 3 is a schematic block diagram of the control section of the copying machine. In the zoom copying machine of this embodiment, the master C controls the entire copying machine.
This is performed using a PU board 30 and a slave CPU board 31 connected to it via a communication line 32. The slave CPU boat 31 is a mirror motor (BL) for driving the scanner.
M) 29, the solenoid PSC 24 for driving the PS roller 22, and the lens drive motor (STM) 25 are controlled respectively, and from the motor sensor (including a rotary encoder, etc.) attached to the rotating shaft of the mirror motor 29. and signals from various sensors such as an MHP sensor that detects the home position of the scanner and an HP sensor (not shown) that detects the home position of the lens 17. Reference numeral 26 denotes a static elimination lamp, which, as shown in FIG. 1(A), is composed of an LED array consisting of nfllj LEDs. Each of them is turned on/off by a signal output from the ED master CPU board 30. Reference numeral 27 denotes an operation board for setting copying magnification and trimming area.

Description of fbl operation The portion to be trimmed is designated by operating the operation board 27. For example, if you want to erase only the hunting part in FIG. 1(B), input the position 5-tuv. In the copy cycle, the original image formed on the photoreceptor is processed by turning on the LED at the corresponding location of the static elimination lamp 26 corresponding to s-L in the drum axis direction of the photoreceptor drum 6, as shown in FIG. 1(A). By turning on the light, static electricity can be removed from that part. Since the conveying directions s-u and tv of the copy paper correspond to the rotating direction of the photoconductor drum, the lighting and extinguishing timing of the Pa-Pb LED of the static elimination lamp is determined based on the scanner position data. I need to decide.

FIG. 4 is a time chart showing the control contents of the slave CP [J board 31]. First, a normal copying operation will be explained.

When a normal original is set on the original table and a copy button (not shown) is pressed, the scanner starts to move from the MHP position. The moving speed at this time is determined by the setting magnification set by the operator in advance. The moving speed NF is set by the slave CPU board 3I receiving data on the set magnification from the master CPU 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 moves to MIIP.
It crosses sensor I9 at some point. Let this point be t2,
Let the start time of the scanner be tl. slave CP
The tJ board 31 has an internal counter and a timer, and at time t2, the counter starts counting pulses input from the rotary encoder. As described above, the distance from the home position MHP to the leading edge position of the document is constant regardless of the set magnification. The slave CPU board 31 determines that the scanner has reached the leading edge position A of the document when the counter corresponds to this fixed distance. Specifically, the master CPU
A count value corresponding to the certain distance is received from the board 30, and the value is set in a counter in the slave CP t, J board.

Let this value be (PSC-A). Next, each time a pulse is received from the low reencoder, the count value is subtracted by one, and when the count value reaches 0, a count amplifier signal is generated. This count-up signal detects that the scanner has reached the leading edge position A of the document. Note that at this point, the image at the leading edge of the document is exposed at the exposure point a of the photoreceptor drum 6.

When the count amplifier signal is generated, the slave C
A timer within the PU board 31 starts.

This timer measures the time it takes for the image at exposure point a to reach point b (see Figure 2) of the transfer section at speed NO, and the time it takes for the leading edge of the transfer paper to reach the above point from the position of the PS roller 22. It is for adjustment. The timer time is the value obtained by subtracting the time required for the leading edge of the transfer paper to reach the above-mentioned point from the position of the Y/S roller 22 from the time required for the image on the photosensitive drum to reach the point a to point b. This timer time (PS
CB). When the slave CPU board 31 starts this timer and detects a time-up signal after the time (PSC-B) has elapsed, the PS roller's Furano 1000 PS C2
Turn on 4. Through this control, the leading edge of the image formed on the photosensitive drum at point b can be made to coincide with the leading edge of the transfer paper.

1) When the constant magnification changes, the scanner's moving speed N
Although F changes, the pulse formed by the rotary encoder is generated once every time the scanner moves a certain distance, so it is always counted when the scanner reaches the document leading edge position A point, regardless of the moving speed NF. An amplifier signal is generated.

Next, the operation when performing trimming as shown in FIG. 1(B) will be described.

As shown in FIG. 2, the position on the drum directly below the static elimination lamp is C, and the distance between a and c is xO. The position of the scanner when the leading edge of the original image on the photosensitive drum is at point C (
If the value of the counter representing
The number of pulses lO during that time is determined by the following equation.

ff1O=xo/Δl Here, Δl represents the distance around the photosensitive drum corresponding to one pulse of the rotary encoder. Note that the above equation applies when the copying magnification is the same (the peripheral speed of the photosensitive drum and the moving speed of the scanner are equal), and the general equation when changing the magnification is as follows.

1O=xO/(Δl-Z) Here, Z represents the copy magnification.

Next, let the value of the counter when the scanner reaches the position corresponding to the s-t line shown in FIG. 1(B) be A1,
If the value of the counter when the u-v line is reached is A2, then AI=AO+xl/Δ1 A2=AO+x2/Δl Also, AO=
(PSC-A)-eo-(PSC-'A)-XO/(Δl·Z).

Therefore, Al and A2 can be expressed as in the following equation.

AI= (PSC-A)-xO/ (Δf-Z)+XI
/Δ1 A2= (PSC-A)-xo/ (Δf-Z)+x2
/Δl Expressed as a general formula, A = (PSC-A) - (xo/Δ1) (1/Z) x
/Δl. Here, XO/Δl and Δ2 are constants.

Based on the above relationship, the on/off timing of the static elimination lamp (BL) is determined by the copy paper leading edge adjustment value (PSC-A
), the copying magnification Z, and the data (xi, x2) representing the trimming location. That is, as shown in Fig. 4, the count number l is from AO to Xi/Δ
2, and A2 corresponds to the count number of X2/Δβ from AO, and is independent of the copying magnification.

In this way, the counter calculates the timing corresponding to the difference in timing (lO) required for the photosensitive drum to move from the static elimination 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). The timing of driving the static elimination lamp is controlled based on AO.

FIG. 5 shows an example of trimming another document, and FIG. 6 shows its timing chart. As shown in Figure 5, P a - P d Ill xl in the width direction of the copy paper
This represents the case where an area of -x2 and an area of xi-x3 in the transport direction are erased by Pa'-Pb' in the width direction. As shown in FIG. 6, the scanner moves during the copy cycle, the counter starts counting from the home position (t2), and the value is AI=(PSC-A)-10+xl/Δ
1, L17.1 corresponding to the erase area Pa-Pb and Pa'-Pb' lines among the n LEDs of the static elimination lamp.
r) lights up. Furthermore, when the counter value reaches A2, P
The LED on the a-Pb line lights up white, and the counter value is A.
When it reaches 3, the LED on the Pa′-Pb′ line goes out. In addition, here, the width of the LED on the Pa-Pb line is W
When the width of the LED of the line 1, Pa'-Pb' is W2, it is obtained as Wl-Pa-Pb-Z W2=Pa'-Pb'.Z.

Here, Z is the copy magnification.

The on/off timing of the static elimination lamp is controlled in the above manner. In the embodiment, the static elimination lamp was disposed in front of the exposure point with respect to the moving direction of the photosensitive drum, but it is also possible to dispose the static elimination lamp behind the exposure point. In this case, the distance xO between point a and point 0 is a negative value.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) are diagrams for explaining a trimming method in a copying machine having a trimming function, which is an embodiment of the present invention, and FIG. 1(A) shows the relationship between the photoreceptor drum and the static elimination lamp. , FIG. 1(B) is a diagram showing a document and its trimming area. Figure 2 is a schematic diagram of the copying machine;
The figure is a schematic block diagram of the control unit of the copying machine, and Figure 4 is the first
FIG. 7 is a timing chart showing the timing of each part of the control unit when performing the trimming shown in FIG. 3(B). FIG. FIG. 5 is a diagram showing another example of trimming a document, and FIG. 6 is a timing chart showing the timing of each part of the control section in that case. 6-photosensitive drum, 26-static elimination lamp.

Claims (1)

[Claims] (1) a home position detection sensor that detects the home position of the document scanner; a pulse forming unit that forms a number of pulses corresponding to the moving distance of the scanner; and counting of the pulses from the time when the scanner passes the home position. has a counter to start, and
The apparatus further includes a static elimination lamp for trimming a desired area of the document along the photoconductor, and means for determining a timing difference required for the photoconductor to move from the static elimination lamp to the exposure point or from the exposure point to the static elimination lamp. , a control means for controlling the timing at which the static elimination lamp is driven based on a timing corresponding to the timing difference from the value of the counter corresponding to the leading edge position of the document;
A copying machine having a trimming function.