JPH1097111A - Registration clutch control device - Google Patents

Abstract

(57) Abstract: Provided is a registration clutch control device that performs 0N-OFF control of a registration clutch without affecting processing time of a control microcomputer. SOLUTION: An offset register 9 is previously set by a microcomputer.
The time from the detection of the leading edge signal of the transition detector 6 to the ON of the registration clutch and the time from the ON to the OFF of the registration clutch are recorded in a and 9b, respectively. The output value of the count register 8 is fetched, the control mode is set by the mode setting device 12, the offset selector 10 selects one of the recording times of the offset registers 9a and 9b in the setting mode, and the output latch circuit 17 A clutch control signal is output based on the output values of the capture register 13, the offset selector 10, and the timer count register 8, the mode detection latch circuit 19 notifies the microcomputer of the mode, and the register clutch 0N-0FF influences the processing of the microcomputer. Done with high precision without.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a registration clutch control device which is incorporated in an image forming apparatus and controls the transfer of a transfer sheet by turning a registration clutch on and off.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine has a built-in registration clutch control device for ON / OFF controlling a registration clutch for driving a registration roller for conveying a transfer sheet to an image forming unit. A one-shot timer is set by an interrupt of the microcomputer for use, and after a first predetermined time elapses after the detection sensor detects the document, the registration clutch control device controls the registration clutch to ON to drive the registration roller and transfer the image. The conveyance of the paper to the image forming unit is started, and after a lapse of a second predetermined time after the detection of the document by the detection sensor, the registration clutch control device controls the registration clutch to be turned OFF, and the registration roller corresponds to the next transfer paper And stop.

[0003]

However, since the microcomputer that controls the registration clutch control device controls the entire image forming apparatus, the processing on the microcomputer side is complicated, and the detection signal of the original is generated. It takes time to set the one-shot timer after receiving, or it takes time to control the registration clutch to 0FF after receiving the interrupt signal from the one-shot timer, delaying the registration clutch OFF control timing. May be.

As described above, if the setting time of the one-shot timer or the time from the reception of the interrupt signal from the one-shot timer to the control of the registration clutch is delayed due to the complicated processing on the microcomputer side, the image forming unit will Synchronization between the image forming operation and transfer-in of the transfer paper may not be achieved, and an image with a positional shift may be formed.

The present invention has been made in view of the current state of registration clutch control in an image forming apparatus as described above, and has as its object the purpose of controlling the registration clutch without being affected by the processing time of a control microcomputer. An object of the present invention is to provide a registration clutch control device capable of performing 0N-OFF control.

[0006]

According to a first aspect of the present invention, there is provided an image forming apparatus which is incorporated in an image forming apparatus and outputs a clutch control signal based on a signal from a microcomputer. Is a register clutch control device that controls the transfer of the transfer paper to the image forming unit by turning ON and OFF the timer, a timer count register that counts a reference clock, and a transition detector that detects a document leading edge signal from a document reading unit. A first offset register in which the time from the detection of the document leading edge signal by the transition detector until the registration clutch is turned on is recorded; and a time from the time the registration clutch is turned on to the time it is turned off is recorded. Based on the second offset register, based on the detection of the document leading edge signal by the transition detector, A capture register for capturing an output value of the timer count register, a mode setting device for setting a mode of the control process of the registration clutch, and recording of the first offset register based on the mode set by the mode setting device. An offset selector for selecting and outputting one of a time and a recording time of the second offset register, an output value of the capture register, an output value of the offset selector, and an output value of the timer count register. ON-OFF the resist clutch
And a latch circuit for holding and outputting a control signal to be output.

Similarly, in order to achieve the above object, a second aspect of the present invention is the same as the first aspect, except that a mode detection latch circuit for detecting a mode set by the mote setting device is provided. It is characterized by having.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a main part of the present embodiment, FIG. 2 is a block diagram showing a configuration of a registration clutch control device of FIG. 1, and FIG. 3 is a time chart showing a first half operation of the present embodiment. 4 is a time chart showing the latter half operation of the present embodiment.

An image forming apparatus incorporating this embodiment includes a control microcomputer 1 for controlling the entire image forming apparatus, a document reading device 2 for reading a document, and carrying a transfer sheet into the image forming unit. A registration clutch control device 3 for performing 0N-0FF control of a registration clutch for driving a registration roller is provided. As shown in FIG. 1, the control microcomputer 1 is connected to the document reading device 2 and the registration clutch control device 3. Document reading device 2
Is connected to the registration clutch control device 3,
A driver 4 that controls ON / OFF of the registration clutch is connected to the registration clutch control device 3, and a registration clutch 5 is connected to the driver 4.

The registration clutch control device 3 has a configuration as shown in FIG. 2, and an initialization signal decoder 11 for outputting a signal for set / reset based on an initialization signal from the control microcomputer 1. A transition detector 6 for detecting a leading edge signal from the document reader 2, a mode setting unit 12 for setting a mode of a control process of the registration clutch, and an output latch circuit 17 for outputting a clutch control signal. The transition detector 6 is connected to one input terminal of an OR circuit 7 and a transition detection latch circuit 18 for outputting a transition detection signal, and the mode setter 12 detects a mode set by the mode setter 12. Mode detection latch circuit 19 is connected.

An offset register 9a which receives offset data from the control microcomputer 1 and records the time from when the transition detector 6 detects the leading edge signal of the document to when the registration clutch is turned on, and when the registration clutch is turned on.
An offset register 9 comprising an offset register 9b for recording the time from the start to the OFF is provided. An output terminal of the offset register 9 is connected to an offset selector 10 for selecting the offset registers 9a and 9b. Have been.

On the other hand, a timer count register 8 for counting the reference clock is provided. The timer count register 8 captures the output value of the timer count register 8 based on the detection of the leading edge signal of the document by the transition detector 6. Connected to register 13, capture register 1
3 is connected to an adder 14 that adds the output value of the offset selector 10 and the output value of the capture register 13.

A match register 15 for recording the added value of the adder 14 is connected to the adder 14, and the output terminals of the match register 15 and the timer count register 8 have the recorded value of the match register 15 and the timer count register 8 connected thereto. A comparator 16 for comparing the recorded value of the register 8 with the comparator 16 is connected.
Is connected to an output latch circuit 17 for outputting a clutch control signal and the other input terminal of the OR circuit 7. Further, an output terminal of the OR circuit 7 is connected to a capture register 13, an adder 14, and a coincidence register 15.

The operation of this embodiment having such a configuration will be described. The timer count register 8 is a 16-bit free-running counter that counts a reference clock having a period of 32 μsec.
As shown in FIG. 3 (g), when the resist ON time is divided by 32 μsec of the reference clock cycle, for example, when the resist ON time is 23 msec, 718 (2CFh in hexadecimal) is written. Similarly, the control microcomputer 1 sets in advance in the offset register 9B a value obtained by dividing the resist OFF time by 32 μsec of the reference clock cycle, for example, the resist OFF time is 1 sec as shown in FIG. , 31250 (7A12h in hexadecimal)
Write.

Next, the control microcomputer 1 supplies an initialization signal bit1 = 1, bit
0 = 0 is written, and a clear signal is output from the initialization signal decoder 11 by writing bit1 = 1. The clear signal initializes the transition detector 6 and the mode setter 12, and FIG. ), The mode setting device 1
2, "mode 0" is set, and a reset signal is output from the initialization signal decoder 11 by writing bit = 0, and the output latch circuit 1
7 is reset, and the clutch control signal goes low as shown in FIG. The transition detection latch circuit 18 is cleared by a transition detection clear signal from the control microcomputer 1.

In this state, a start signal is output from the control microcomputer 1 to the document reading device 2 to start the reading operation of the document, and at the same time, the transfer paper is conveyed to the registration rollers from a paper feeding unit (not shown). In this case, the output latch circuit 17
Is low, the driver 4 does not drive the registration clutch 5, the registration clutch is OFF, and the leading end of the transfer paper stops at the registration roller position.

In this case, when the document reading operation is started, the scanner is activated, and the document reading device 2 outputs a low level document leading edge signal as shown in FIG. 3 transition detector 6
, And the transition detector 6 outputs a detection signal as shown in FIG. 6B. With this detection signal, the transition detection latch circuit 18 outputs the detection signal as shown in FIG.
A high level transition detection signal is output.

At this time, when the transition detector 6 detects the falling edge of the document leading edge signal, even if the document leading edge signal falls again until the clear signal is input from the initialization signal decoder 11, No detection signal is output from the transition detector 6.

In response to the detection signal from the transition detector 6, the capture register 13 changes the recorded value (1000h in this case) of the timer count register 8 shown in FIG.
The reference time is set by taking in the data as shown in FIG.
At this time, since the mode is “mode 0”, the offset register 9a is selected by the offset selector 10, and the adder 14
As a result, the value 02CFh corresponding to the registration clutch ON time is added to the reference time, and the added value 12CFh is taken into the coincidence register 15 as shown in FIG.

The transition detection latch circuit 18 is set by the detection signal from the transition detector 6, and the transition detection signal is input from the transition detection latch circuit 18 to the control microcomputer 1, and the original is read by the original reading device 2. The beginning is detected by the control microcomputer 1.

When the control microcomputer 1 detects the start of reading of the original, a transition detection clear signal is input to the transition detection latch circuit 18, and the logical value of the transition detection signal is set in order to avoid affecting the control operation of the registration clutch 5. Is set to the low level.

When the ON time of the registration clutch 5 is reached after the leading edge signal of the document is detected by the transition detector 6, the output value of the timer count register 8 and the output value of the coincidence register 15 become equal. The comparator 16 outputs a coincidence signal, and the coincidence signal causes the clutch control signal from the output latch circuit 17 to go high, the driver 4 drives the registration clutch 5 and the registration clutch 5 is turned on.

When the registration clutch 5 is turned on,
The transfer of the transfer paper to the image forming unit is started, and the toner image of the photoconductor and the transfer paper arrive in synchronization with the transfer device position,
The photoconductor toner image is transferred to the transfer paper.

When the coincidence signal of the comparator 16 is input to the capture register 13 via the OR circuit 7, the capture register 13 captures the recorded value of the timer count register 8 (12 CFh in this case).
A new reference time is set, and “mode 1” is set by the mode setting unit 12 according to the coincidence signal from the comparator 16. Then, the offset register 9b is selected by the offset selector 10 according to the switching signal from the mote setting unit 12, and the value 7A12h corresponding to the registration clutch OFF time is added to the new reference time 12CFh, and FIG. The added value 8CE1h is taken into the match register 15 as shown in FIG.

In this state, when the time reaches the register 0FF, the recorded value of the timer count register 8 and the recorded value of the coincidence register 15 become equal, so that the comparator 16 outputs a coincidence signal, and the clutch control from the output latch circuit 17 The signal becomes low level, the driving of the driver 4 is stopped, and the registration clutch 5 enters the OFF state.

The mode setting unit 12 sets "mode 2" according to the coincidence signal from the comparator 16, the mode detection latch circuit 19 outputs a mode end signal by the mode detector 12, and the control microcomputer 1 The end of the control of the registration clutch is detected, and the mode detection latch circuit 19 receives a mode end clear signal from the control microcomputer 1.
Is cleared in preparation for the next transfer sheet.

As described above, according to the present embodiment, the offset microcomputer 9a is controlled by the control microcomputer 1 in advance.
Then, from the detection of the document leading edge signal, the registration clutch 5 is turned on
The time from when the resist clutch 5 is turned on to when the resist clutch 5 is turned off is recorded in the offset register 9b. The mode setting unit 12 outputs the clutch control signal output from the output latch circuit 17 from the start of the control operation of the resist clutch 5. Mode 0 until the clutch control signal goes high, mode 1 until the clutch control signal goes low until the clutch control signal goes low, and the control operation of the resist clutch 5 ends when the clutch control signal goes low. Mode 2 is set.

Then, the recorded value of the time taken from the timer count register 8 and the recorded value of the time of the offset registers 9a and 9b selected by the offset selector 10 corresponding to the mode set by the mode setting device 12. , The high level and the low level of the clutch control signal from the output latch circuit 17 are switched, the ON / OFF control of the resist clutch 5 is performed, and the mode detection latch circuit 19 controls the end of the mode. Is detected by the microcomputer 1.

Therefore, according to the present embodiment, 0N-0FF control of the registration clutch 5 is performed based on the time record value of the timer count register 8 for counting the reference clock and the time record value of the offset registers 9a and 9b. The control mode is accurately detected by the control microcomputer 1, and the ON / OFF control of the registration clutch 5 is performed with high accuracy without being affected by the processing time of the control microcomputer 1.
It is possible to cause the image forming apparatus to perform high-quality image formation without image shift.

[0030]

According to the first aspect of the present invention, the time from the detection of the document leading edge signal by the transition detector to the turning-on of the registration clutch is previously stored in the first offset register by the microcomputer. In the register,
The time from when the registration clutch is turned on to when it is turned off is recorded. When the transition detector detects the leading edge signal of the document from the document reading unit,
The output value of the timer count register for counting the reference clock is fetched, the mode of the control process of the registration clutch is set by the mode setting device, and the first offset is set by the offset selector based on the mode set by the mode setting device. Either the recording time of the register or the recording time of the second offset register is selected and output, and the latch circuit is used by the latch circuit based on the output value of the capture register, the output value of the offset selector, and the output value of the timer count register. A clutch control signal for turning on and off the printer is held and output, and conveyance of the transfer paper to the image forming unit is controlled by the clutch control signal.
0N-0FF of the registration clutch can be performed with high accuracy without being affected by other processing of the microcomputer.

According to the second aspect of the present invention, in addition to the effect obtained by the first aspect of the present invention, since the mode set by the mote setting device is detected by the mode detection latch circuit, the control process of the registration clutch is performed. Is accurately notified to the microcomputer, and the control of the registration clutch is performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a main part of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a registration clutch control device of FIG. 1;

FIG. 3 is a time chart showing the first half operation of the embodiment.

FIG. 4 is a time chart showing a latter half operation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control microcomputer 2 Document reading device 3 Registration clutch control device 4 Driver 5 Registration clutch 6 Transition detector 8 Timer count register 9a, 9b Offset register 10 Offset selector 11 Initialization signal decoder 12 Mode setting device 13 Capture register 15 Match register Reference Signs List 16 comparator 17 output latch circuit 18 transition detection latch circuit 19 mode detection latch circuit

Claims (2)

[Claims] An output unit that outputs a clutch control signal based on a signal from a microcomputer;
A resist clutch control device that controls the transfer of transfer paper to the image forming unit by turning on and off the resist clutch. A timer count register that counts the reference clock, and a transition that detects the leading edge signal from the document reading unit A first offset register in which a time from the detection of the document leading edge signal by the transition detector to the ON of the registration clutch is recorded; and a time from the ON to the OFF of the registration clutch. A second offset register in which the register value is recorded; a capture register that captures the output value of the timer count register based on the detection of the document leading edge signal by the transition detector; and a mode for controlling the registration clutch. Mode setting device to perform, and the mode set by the mode setting device Based on the first
An offset selector for selecting and outputting one of the recording time of the offset register and the recording time of the second offset register, the output value of the capture register, the output value of the offset selector, and the output value of the timer count register. ON, the registration clutch is turned ON-
And a latch circuit for holding and outputting a control signal for turning off. 2. A registration clutch control device according to claim 1, further comprising a mode detection latch circuit for detecting a mode set by said mote setting device.