JPH0477309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying machine, and particularly to a variable magnification copying machine. More specifically, the present invention relates to a variable magnification copying machine using a microprocessor (hereinafter referred to as μP) for control, which has an improved interrupt signal processing method.

Generally, in a copying machine using μP, predetermined control is performed by monitoring the state of sensors provided in each part of the copying machine.

In this case, a clock signal (hereinafter referred to as an M/C clock) synchronized with the rotation of the photosensitive drum is supplied to the control device in order to maintain synchronization of the operations of each controlled section of the copying machine.

Since the M/C clock requires high-speed response, it is input to the μP interrupt terminal.

Control using such μP can be performed using optical lenses and
An example of a conventional copying machine control device applied to a variable magnification copying machine that can change the magnification and focus by setting the position of the mirror with an appropriate drive device such as an electric drive device (for example, a pulse motor). is shown in Figure 1.

In the figure, 1 is a control μP equipped with a central processing unit 101, a read-only memory 102, a random access memory 103, an input/output interface 104, and a common bus 105 for data transmission between these, and 2 is a copying machine. photosensitive drum, 3
4 is a lens and a mirror for forming an image of an original (not shown) placed on a platen onto the photosensitive drum 2; 5 is an M/C that serves as a reference for control according to the rotation of the photosensitive drum 2; This is an M/C clock generating element that generates a clock.

6 is a lens reference position sensor that generates a signal when the lens 3 is at the reference position, and 7 is a mirror reference position sensor that generates a signal when the mirror 4 is at the reference position.

2M is the input/output interface 10 of μP1
This is a motor that is rotated by a drive signal a supplied via 4 and drives the photosensitive drum 2. 3M
and 4M are drive signals f, similarly from μP1,
These are stepping motors that are driven by the respective motors b and are used to control the positions of the imaging lens 3 and the mirror 4 according to the set magnification.

Also, INT0 to INT2 are the interrupt pins of μP1,
I0 to I2 are M/C clock signals c, respectively.
This is an interrupt input buffer for inputting the lens position detection signal d and the mirror position detection signal e to the corresponding interrupt terminals INT0 to INT2.

During operation, when μP1 generates drive signal a,
The photosensitive drum 2 is driven and begins to rotate. In response, M/C clock generating element 5 generates M/C clock signal c.

This signal is taken into μP1 via interrupt input buffer I0 and interrupt terminal INT0. As is well known, this M/C clock signal c
is used to determine the control timing of each part of the copying machine.

When setting the copy magnification, when the lens 3 is at the reference position, the lens reference position sensor 6 detects this and produces an output (lens position detection signal) d,
This is the interrupt input buffer I1 and the interrupt terminal
It is taken into μP1 via INT1. Thereafter, the lens drive motor 3M is activated, and the lens 3 is moved by a predetermined distance determined in advance according to the magnification.

Regarding the mirror 4, its reference position is similarly detected by the mirror reference position sensor 7, and the mirror position detection signal e is taken into μP1 via the interrupt input buffer I2 and the interrupt terminal INT2. , driving and setting are performed by a predetermined distance from the reference position.

In this case, if the detection accuracy of the reference positions of the lens 3 and mirror 4 is poor, the setting of magnification and focus will be inaccurate, making it impractical. In order to improve the detection accuracy of the reference position, as described above, the sensor detection signal is applied to the μP interrupt terminal for high-speed response processing.

Conventionally, as shown in FIG. 1, the M/C clock signal c, the lens position detection signal d, and the mirror position detection signal e were supplied to separate interrupt input terminals of μP1. For this reason, the required number of interrupt input terminals increases, resulting in a complicated structure and increased costs.

In order to eliminate and improve the drawbacks of the prior art, the present invention inputs the M/C clock signal and either the lens position detection signal or the mirror position detection signal to the same interrupt terminal of μP, and This reduces the number of terminals required.

That is, the present invention was made based on the following considerations.

(1) Since the M/C clock signal c is generated in synchronization with the rotation of the photosensitive drum, it is supplied to the control section only when the copying process is being performed.

(2) The positions of lenses and mirrors are set before the copying process is started, and the lenses and mirrors are not moved while the copying process is being performed.

(3) As is clear from (1) and (2) above, M/C
The clock signal c and the lens position detection signal d or the mirror position detection signal e are never generated at the same time.

(4) Therefore, one common interrupt pin of μP,
If the M/C clock signal is supplied while the copying process is being performed, and the lens position or mirror position detection sensor output is supplied while the copying process is not being performed, one interrupt can be generated. The terminal can perform interrupt processing for the M/C clock signal and the lens position or mirror position detection signal.

The present invention will be explained in detail below with reference to the drawings. FIG. 2 shows an embodiment of the present invention, and the same reference numerals as in FIG. 1 represent the same or equivalent parts.

8 is a signal selection switching circuit newly added according to the present invention in place of the conventional interrupt input buffers I0 and I1.

The signal selection switching circuit 8 selects a drum drive signal a.
an AND gate 81 which has two inputs each of the inverted signals of the drum drive signal a and the inverted signal of the M/C clock signal c, an AND gate 82 which has two inputs of the inverted signals of the drum drive signal a and the lens reference position detection signal d; It consists of an OR gate 83 to which the outputs of AND gates 81 and 82 are supplied. The output of the OR gate 83 becomes an interrupt signal g to the interrupt terminal INT1.

If you try to set the copy magnification before starting the copy operation and operate the magnification setting button on the panel,
The respective drive motors 3M and 4M are activated by the output signals f and b of μP1, and the lens 3 and mirror 4 are first driven toward the reference position. When these reach the reference position, a lens reference position detection signal d and a mirror position detection signal e are generated (in this example, each becomes low level).

At this time, since μP1 is not generating the drum drive signal a and the drum drive signal a is at a high level, the AND gate 81 is closed and the AND gate 82 is open. Therefore, the lens reference position detection signal d is input to the interrupt terminal INT1 via the AND gate 82 and the OR gate 83.

In response to this interrupt input, μP1 reads the number of pulses required to move the lens 3 to a position corresponding to the set magnification from, for example, a table stored in advance in the internal memory. Then, the above number of pulses is supplied to the motor 3M via the input/output interface 104. This causes the motor 3M to rotate and move the imaging lens 3 to a position corresponding to the set magnification.

The third flowchart shows the operation of μP1 when the lens reference position detection signal d is generated and supplied to the interrupt terminal INT1, and an interrupt is performed.
It will look like the figure. Since FIG. 3 is obvious at first glance, a detailed explanation thereof will be omitted.

Further, as in the conventional example, the mirror position detection signal e is sent to the interrupt terminal via the interrupt input buffer I2.
Input to INT2. The operation in this case is similar to that described above regarding the lens 3.

When a copying operation begins, a drum drive signal a is generated (in this example, a goes low).
As a result, AND gate 81 is opened and AND gate 82 is closed. Therefore, the M/C clock generated as the photosensitive drum 2 rotates is inputted to the interrupt terminal INT1 via the AND gate 81 and the OR gate 83.

As is well known, at the time of an interrupt based on M/C clock generation, various controls (for example,
(drum rotation detection, rotation state detection, M/C clock counting, etc.), but the most typical example is M/C clock counting.

That is, as shown in the flowchart of FIG. 4, an interrupt is generated each time the M/C clock c is input to the interrupt terminal INT1, and the count value of the clock counter is updated by one. μP1 controls, for example, the timing of paper feeding and the blinking of the illumination light source, according to the count value.

As can be seen from the above description, according to this embodiment, the interrupt input to the interrupt terminal INT1 is selected and switched by the signal selection switching circuit 8 depending on the operating state of the copying machine.

That is, as the interrupt signal g to the interrupt terminal INT1, when the drum drive signal a is generated and is at a low level, that is, during the copying operation, the M/C clock signal c is selected; When the drive signal a is not generated and is at a high level, that is, when no copying operation is being performed, the lens reference position detection signal d is selected.

In the above, AND gates 81 and 82 were provided in the signal selection switching circuit 8 to separate the signals, but as mentioned above, in the normal case,
Since the M/C clock signal c and the lens reference position detection signal d are not generated simultaneously, they can be omitted. Also, in Figure 2,
It goes without saying that the lens reference position detection signal d and the mirror position detection signal e may be interchanged.

Furthermore, the signals that share the interrupt terminal with the M/C clock signal c are not limited to the lens reference position detection signal d and the mirror position detection signal e mentioned above, and may be generated simultaneously with the M/C clock signal c. It is clear that any type of signal may be used as long as it is such that there is no such signal.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a copying machine control device for explaining a conventional interrupt signal processing method, and FIG.
FIG. 3 is a schematic block diagram of a control device for a copying machine showing an embodiment of the present invention, FIG.
FIG. 4 is a flowchart showing an example of the operation when interrupted by the M/C clock. 1...Microprocessor, 2...Photosensitive drum, 3...Lens, 4...Mirror, 5...M/C
Clock generating element, 6...Lens reference position sensor, 7...Mirror reference position sensor, 8...Signal selection switching circuit, INT0 to INT2...Interrupt terminal,
a...Drum drive signal, g...Interrupt signal, c...
...M/C clock signal, d...Lens reference position detection signal, e...Mirror position detection signal.

Claims (1)

[Scope of Claims] 1. A control microprocessor having first and second interrupt terminals, a photosensitive drum rotated by a drive signal output from the microprocessor, and a photosensitive drum placed on a platen. A variable copying magnification type comprising a lens and a mirror for forming an image of the original document on the photosensitive drum at a set copying magnification, and capable of changing the copying magnification by adjusting the positions of the lens and mirror. A copying machine comprising: a clock signal generating means for generating a clock signal synchronized with the rotation of the photosensitive drum; a lens reference position sensor for detecting the reference position of the lens; and a mirror reference position sensor for detecting the reference position of the mirror; When the microprocessor is not outputting a drum drive signal, either the lens position detection signal or the mirror position detection signal is input to the first interrupt terminal, and when the drum drive signal is output, the clock signal is input to the first interrupt terminal. Signal selection switching means for inputting the clock generated by the generating means to the first interrupt terminal; and means for inputting the other of the lens position detection signal and the mirror position detection signal to the second interrupt terminal. A copying machine characterized by the following.