JPH10232520A - Image forming device provided with document feeder and data communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of communicating between an image forming device main body and a document feeder, with a simpler hardware constitution. SOLUTION: The CPU 601 of an automatic document feeder 600 and the CPU 701 of a copying machine main body 700 are connected to each other by signal conductors 721-725. At the time of supplying power, the CPU 601 outputs a synchronizing signal to the signal conductor 722 of a code 0 and serially a verso number to the signal conductor 723 of a code 1 in synchronization with the synchronizing signal. The CPU 701 periodically monitors the synchronizing signal of the signal conductor 722 and conforms the signal level of the data of the signal conductor 723, to recognize the version number, wherever a change in the synchronizing signal is detected. Further, the signal conductors 722 and 723 can be used in common to transmit the data on a jam occurrence class and a document size. These data are arranged with a feeding completion reporting signal 724 and a jam occurrence signal 725 which are outputted by the CPU 601.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, and more particularly, to a method and an apparatus for communication between a document feeder and an image forming apparatus main body.

[0002]

2. Description of the Related Art Some image forming apparatuses such as copying machines are equipped with a device for automatically feeding a document to be copied as a standard equipment, or can be attached as an option. As such a document feeder, a type using a central processing unit (CPU) independent of an image forming apparatus main body is known because of its expandability and flexibility.

The CPU of this document feeder needs to exchange data with the CPU of the main body of the image forming apparatus.
In general, when performing communication between CPUs, parallel communication for transmitting data in parallel is suitable for transmitting a large amount of data at high speed, but has a disadvantage that the number of signal lines between the CPUs increases. On the other hand, serial communication in which data is transmitted serially has an advantage that data transmission speed is low but communication can be performed with a small number of signal lines.

[0004]

In general, serial communication is employed for communication between the image forming apparatus main body and the CPU of the document feeder even if a relatively small amount of data is transmitted at a low speed. . However, for this purpose, a UART (Universal As
A dedicated LSI for serial communication, called an "ynchronous Receiver Transmitter", is used, and the hardware configuration is complicated and the cost is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of performing communication between an image forming apparatus main body and a document feeder with a simpler hardware configuration.

[0006]

According to an image forming apparatus with a document feeder according to the present invention, the main body of the image forming apparatus is a first CP.
U, the document feeder has a second CPU, the first and second CPUs are connected by first and second signal lines, and the second CPU When the power of the forming apparatus is turned on, a synchronization signal that is turned on and off at a constant cycle is output on the first signal line, and serial data is output on the second signal line in synchronization with the synchronization signal,
The first CPU periodically monitors a synchronization signal on the first signal line, and at each time when detecting a change in the synchronization signal,
The serial data is recognized by confirming a signal level of the serial data on the second signal line.

According to this configuration, the first CPU is directly connected between the two CPUs.
And data communication can be performed by connecting with the second signal line, and the hardware configuration can be simplified.

The serial data is, for example, a version number of the document feeder.

The first and second signal lines can be used for transmitting data different from the serial data.

Specifically, the first and second CPUs
Are further connected by a third signal line, and the second C
The PU outputs a pulse signal indicating a paper feed completion report on the third signal line every time the feeding of one document is completed, and outputs the pulse signal on the first and second signal lines. The size data of the completed original is output, and the first CP
U periodically monitors the signal level on the third signal line, and when detecting the generation of the pulse signal, confirms the signal level of the size data on the first and second signal lines, The original size of the original can be recognized.

[0011] Further, between the first and second CPUs,
Further, the second CPU is connected by a fourth signal line.
Outputs a pulse signal indicating the occurrence of a jam on the fourth signal line when detecting the occurrence of a jam at the time of document feeding, and outputs the type data of the jam on the first and second signal lines. The first CPU periodically monitors a signal level on the fourth signal line, and when detecting the generation of the pulse signal, outputs the jam type data on the first and second signal lines. By checking the signal level, the type of the jam can be recognized.

As described above, the required number of signal lines between CPUs can be reduced by using the first and second signal lines for different purposes depending on the case.

The first and second CPUs are further connected by a fifth signal line, and the first CPU supplies a document to the second CPU when document feeding is required. Outputting a paper request signal on the fifth signal line;
The CPU outputs the first signal outputted on the fifth signal line.
The document can be fed in response to a document feed request signal from the CPU.

A data communication method according to the present invention is a method for performing communication between an image forming apparatus main body having a CPU and a document feeder. Outputs a synchronizing signal that is turned on and off at regular intervals from a first output terminal thereof to a first signal line connected to a first input terminal of the main body CPU, and outputs a synchronization signal to the second CPU of the document feeder CPU. Output serial data in synchronization with the synchronizing signal from an output terminal to a second signal line connected to a second input terminal of the main body side CPU;
The main body side CPU periodically monitors the synchronization signal on the first signal line, and when detecting a change in the synchronization signal,
The serial data is recognized by confirming the signal level of the serial data on the signal line.

The CPU of the document feeder is connected from the third output terminal of the CPU of the document feeder to the third input terminal of the CPU of the main body every time the feeding of one document is completed. A pulse signal indicating a paper feed completion report is output on the third signal line, and the first CPU of the document feeder side CPU
And the second output terminal outputs size data of the completed document on the first and second signal lines, and the main body side CPU periodically monitors the signal level on the third signal line. When the generation of the pulse signal is detected, the document size of the document can be recognized by checking the signal levels of the size data on the first and second signal lines.

The document feeder-side CPU detects the occurrence of a jam when feeding the document, and detects the occurrence of a jam.
A pulse signal indicating the occurrence of a jam is output from a fourth output terminal of the CPU to a fourth signal line connected to a fourth input terminal of the CPU of the main body. 2 outputs the type data of the jam on the first and second signal lines from the output terminal of the main body C
The PU periodically monitors the signal level on the fourth signal line, and when detecting the occurrence of a pulse signal, confirms the signal level of the jam type data on the first and second signal lines, The type of the jam can also be recognized.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the appearance of a copying machine as an example of an image forming apparatus to which the present invention is applied. Before understanding the specific configuration and operation of the present invention, the configuration and operation of the copying machine 100 will be described first.

In the copying machine 100, an original is read from an internal original reading unit (see FIG. 1) by placing an original on an original platen 14, closing an original feeder 61 also serving as an original cover, and pressing a start button on an operation panel 12. The original is scanned by the movement of step 6 (706). The read image is subjected to an electrostatic copying process by a front tray 13, a manual feed tray 74,
The toner image is transferred and fixed to the paper selectively supplied from any one of the roll paper supply units 17, and is discharged to the copy discharge tray 70. The manual feed tray 74
Shows a usable state in the figure, but can be stored in the side of the copying machine when not in use.

In addition to manual feeding, the copying machine 100 shown in FIG. 1 feeds a single-leaf original from the original insertion port 23 by the original feeding apparatus 61, and a plurality of automatic original feeding apparatuses 600 to be described later. It is possible to automatically feed the originals sequentially.

When the original insertion slot 23 of the original feeder 61 is used, the apparatus operates even in a copy mode called a sheet through mode. In the sheet-through mode, the document reading unit is fixedly disposed substantially at the center of the document table 14, and as shown in FIG. As a result, the document is automatically taken in, the document is transported on the document table 14 by the transport belt 11, and is discharged to the document discharge tray 15. In the course of this conveyance, the image of the document is read. In the sheet through mode, (a) a document longer than the size of the document table 14 in the longitudinal direction can be copied;
(B) Since it is not necessary to reciprocally scan the original reading section, the time required for copying one original can be shortened.

In this embodiment, in addition to a document feeder (DF) 61, a plurality of originals are set in the copying machine 100 as shown in FIG. Document feeder for feeding paper, so-called automatic feeder (AF) 600
Attach. In this embodiment, mechanical attachment of the automatic document feeder 600 is performed to the main body of the copying machine 100. The presence or absence of this attachment is detected by a sensor (not shown). Automatic document feeder 60
When 0 is used, the taken document stops on the document table 14 and the document is read by scanning of the document reading unit. That is, copying is performed in a normal mode different from the sheet through mode.

FIG. 4 shows a schematic configuration of the inside of the document feeder 61. FIG. 4 shows a state in which the document feeder 61 is placed on a document table glass 62 constituting the document table 14.
A document is inserted into the document insertion slot 23, and the document input sensor S1
As a result, when the insertion of the document is detected, the paper feed roller 21 starts rotating, and the document is taken inside. When the leading edge of the document is detected by the paper feed sensor S2, the document feeding is temporarily stopped, and a copy start command from the user is awaited. However, when the “auto start” mode is set by the user, the document feeding is continued without a pause.

The time when the leading edge of the document passes through the paper feed sensor S2 and reaches the image sensor S3 is a reference point for calculating the timing of paper transport. That is, the image sensor S3 is a sensor for synchronizing the timings of the document feeding and the sheet feeding. However, this does not mean that sheet feeding is started immediately when the image sensor S3 is turned on. The document that has passed through the image sensor S3 is transported onto the document glass 62 by the transport belt 11 that rotates between the pair of pulleys 24 and 25. In the sheet-through mode, the document passes over the image reading position R while maintaining a constant speed according to the magnification. In the normal copy mode, the original stops on the original platen. When the automatic document feeder 600 is used, the document whose copying has been completed is guided by the guide 30 and is fed to the document feeder 61.
Is discharged onto a document discharge tray 32 at the upper part of the document. In the sheet-through mode, the path is switched by the path switching claw 26 and is discharged to the document discharge tray 15 (FIG. 1) by the discharge roller 28 via the discharge path 27.

FIG. 5 shows the internal structure of the copying machine 100.
Inside the copier 100, a reading optical system 64 is located below the platen glass 62. The reading optical system 64 reciprocates to scan a document in a normal mode, and in a sheet-through mode. , The reading position R. The light image read by the reading optical system 64 is
An electrostatic latent image is formed on a photosensitive drum (image forming unit) 65 via an optical system including a lens system 60. This electrostatic latent image is developed with toner by the developing device 63, and the toner image is transferred onto the conveyed paper. The transferred toner image on the sheet is heated and fixed by the fixing device 68 and is discharged onto a sheet discharge tray 70. The paper is selected from one of the plurality of front trays 13, the manual feed tray 74, and the roll paper 72 of the roll paper feed unit 17, and waits at the position of the paper leading edge sensor 66 prior to image formation. The next waiting sheet is conveyed to the transfer area at a predetermined timing according to the copy mode.

Here, referring to FIG. 6, the copying machine 100 shown in FIG.
A configuration example of the control device will be described. The copying machine 100 includes a main body 700 and an automatic document feeder (AF) 600. As described above, in the present embodiment, the document feeder (D
F) 61 belongs to the main body 700 of the copier 100, and the control of this main body 700 is controlled by a central processing unit (CPU) 701. The automatic document feeder (AF) 600 is provided with a dedicated CPU.

More specifically, as shown in FIG. 6, the main body 700 includes a CPU 701, a ROM 702, and a RAM 70.
3, operation unit 704, display unit 705, document reading unit 70
6, a document transport unit 707, a copy paper transport unit 708, other control units 709, a power supply 710, and a sensor group 711. The ROM 702 stores programs executed by the CPU 701 and various data accompanying the programs in a nonvolatile manner. R
The AM 703 functions as a work area used by the CPU 701 and a temporary storage area for various data. An operation unit 704 and a display unit 705 on the operation panel 12 in FIG. 1 control an interface with a user. Document reading unit 706
Controls the reading optical system 64 described with reference to FIG.
The document conveyance unit 707 has a conveyance motor for driving the document conveyance belt 11 and the like, and conveys a document inserted from the document insertion port 23 or passed from a document feeding unit 607 described later onto the document table 14. Further, it has a function of discharging the copied original to the outside. The copy paper transport unit 708 transports copy paper by a known configuration. Other control unit 709
Is a unit which is not directly related to the present invention, but performs the remaining control necessary for copier operations such as development and fixing. Power supply 71
0 supplies operating power to each part of the main body 700.
In the present embodiment, power is also supplied to the AF 600 from the main body side. The sensor group 711 includes the various sensors S described above.
1, S2, S3, etc. This sensor group 711 includes an AF
During the operation of the AF 600, a CPU 60
The output can be referred to from 1 as well.

On the other hand, the AF 600 has a CPU 601 and an RO
An M602, a RAM 603, a document feeding unit 607, and a sensor group 608 are provided. The CPU 601 controls the AF 600. The ROM 602 non-volatilely stores programs executed by the CPU 601 and various data accompanying the programs. R
The AM 603 functions as a work area used by the CPU 601 and a temporary storage area for various data. The document feeder 607 has a paper feed motor, and the automatic document feeder 600
Has a function of taking out documents one by one from a plurality of documents placed on the document feeder and transferring the documents to the document feeder 61. Sensor group 6
08 includes an AF document input sensor (not shown) for detecting a document input to the AF 600 and a document width sensor for detecting the width of the document. These can be configured using known detection means, for example, mechanical or optical detection means.

The main body 700 and the AF 600 are electrically connected by a signal line group 650 such as a cable.

A specific example of the signal line group 650 will be described with reference to FIG. The signal line group 650 includes the document feed request signal 7
21, a code 0 signal 722, a code 1 signal 723, a paper feed completion report signal 724, a signal line for a jam occurrence signal 725, a power supply line (PWR) 726, and a ground line (GND)
727, and output signals 728 (a plurality of signals) of the sensor group 711. The document feed request signal 721 is sent to the main body 700.
From the output terminal O5 of the CPU 701 to the CPU of the AF 600
This signal is output to the input terminal I5 of the 601. This signal is output when the main body 700 requests the AF 600 to feed a new document. Feed completion signal 724
Is a signal output from the output terminal O3 of the CPU 601 to the input terminal I3 of the CPU 701.
This is output when the document 600 reports that document feeding has been completed in response to a document feeding request from the main body 700. Two signal lines of a code 0 signal 722 and a code 1 signal 723 are connected from output terminals O1 and O2 of the CPU 601 to input terminals I1 and I2 of the CPU 701, respectively.
00 version signal, document size signal, jam occurrence type signal, and the like. Jam occurrence signal 7
25 is an output terminal O4 of the CPU 601 to the CPU 701;
This signal is output to the main body 700 when the AF 600 detects the occurrence of a document jam in response to the output of the sensor group 711 described above. The power supply line (PWR) 726 is a line for supplying operating power from the main body 700 side to the AF 600 side.
The ground (GND) line 727 is a line for providing a common ground potential to each signal and power supply.

Code 0 signal 722 and Code 1 signal 7
When 23 is used for transmitting a version signal (version number stored in the ROM 602) of the AF 600, a synchronization signal is sent to the code 0 signal 722 and serial data is sent to the code 1 signal 723. The version number of the AF 600 is a number assigned in accordance with a change in the function of the AF 600, a change in a program in the ROM 602, and the like. The version signal in the present embodiment is an 8-bit binary number.

FIG. 8 is a timing chart of each signal when a version signal is notified. At time t0 in FIG.
It is assumed that the power of 0 is turned on. At this point, the CPU 70
1 and 601 are both reset, and the output terminal thereof becomes high impedance for a predetermined time. Each signal line other than the power supply line 726 and the ground line 727 is pulled up to a positive voltage via a pull-up resistor (not shown).
High (H) during the high impedance period of the output terminal of U
Level. However, this high level has no particular meaning in the present embodiment. After a predetermined time (600 ms in this example) has elapsed since the power was turned on, the CPU 601 starts outputting a synchronization signal that is turned on and off at a fixed cycle on the signal line of the code 0 signal 722, and also outputs the code 1 signal 723.
, And starts outputting 8-bit data serially in synchronization with the synchronization signal (time t1). In the present embodiment, the synchronization signal is a clock having a period of 200 ms, and outputs 1-bit data every half period (100 ms) of the clock. In the example of the figure, the version signal “1.3”
Binary value "00010011" representing (decimal value)
Is transmitted. Specifically, the code 1 signal 723 is low (L) at the time t1, and then becomes high at the time t2. It goes low at time t3, 100 ms after time t2, and 200 ms after time t3.
It goes high at a later point in time t4. The ninth change in the synchronization signal is detected when the synchronization signal goes high at time t5.
As a result, transmission of the 8-bit version signal ends.

The CPU 701 operates 600 ms after the power is turned on.
After the elapse, the input terminal I to which the code 0 signal 722 is input
1 is periodically checked, and when the high state is detected, the level of the input terminal I2 to which the code 1 signal 723 is input is read. The check cycle is set to be sufficiently shorter than a half cycle of a clock, which is a 1-bit time width, so that data is not read unnecessarily. In this example, 20m
s. Thus, the first bit of the serial data can be recognized. Thereafter, the CPU 701 periodically checks the input terminal I2, and every time the level changes, the code 1 signal 723 (input terminal I2)
Read the level of The transmission of the version signal ends when the 8-bit serial data is read.

As described above, the version signal of the AF 600 can be transmitted by using only two signal lines of code 0 and code 1 (three if the ground line is included). The reference clocks (not shown) of both CPUs 701 and 601 are not synchronized, and it is not guaranteed that the timing at which the CPU 601 starts outputting the synchronization signal of code 0 and the timing at which the CPU 701 starts checking the synchronization signal are exactly the same. But,
By performing a check with a sufficiently narrow width (20 ms) for a 1-bit time width (100 ms), a slight timing shift does not pose a problem. (If a check is performed at a cycle of 20 ms for a width of 100 ms, an opportunity to capture data at least four times is guaranteed.) In addition, since a synchronization signal line (code 0) is used for a data line (code 1), It is not necessary to add a start bit and a stop bit before and after serial data, respectively, unlike the conventional asynchronous serial communication system.

Next, a case where the signal lines of code 0 and code 1 are shared for another purpose will be described with reference to FIG. FIG. 9A shows a case where the code 0 signal 722 and the code 1 signal 723 are used to notify the main body 700 of the type of jam (jam occurrence location or cause) at the time of document jam occurrence. FIG. 9B shows a case where the code 0 signal 722 and the code 1 signal 723 are used to notify the document size of the automatically fed document to the main body 700. In this example, the user can select either the AB series mode or the inch series mode as the document size.

In FIG. 9A, code 1, code 0
When both are "L", it indicates that a document is fed by the AF 600 and a jam occurs due to the simultaneous insertion of the document when the document is inserted into the document insertion slot 23 of the DF during the copy operation. When the code 1 is “L” and the code 0 is “H”, it indicates that a paper jam has occurred in a paper ejection sensor (not shown, but arranged at a subsequent stage of the document table in the document conveyance path). Code 1 is
H "and code 0" L ", the DF image sensor S
3 shows occurrence of a jam. Code 1 and code 0
Are both "H", indicating that a jam has occurred in the document input sensor S1. The occurrence of these jams can be detected according to the output of the corresponding sensor. For example, in each sensor, detecting a delay jam in response to arrival at the sensor later than expected, or detecting a stagnant jam in response to the ON time of the sensor being longer than expected. Can be.

In FIG. 9B, code 1, code 0
Are “L”, A3S or 12 × 18S
Indicates the size of The former is the size in the AB series mode, and the latter is the size in the inch series mode. Code 1 is
L4 and code 0 is "H", B4S or 11
Indicates the size of × 17S. Code 1 is “H”, code 0
Is "L", it indicates the size of A4s. When both code 1 and code 0 are “H”, it indicates the size of B5S, legal S or letter S.

The types of jams and the number of document sizes shown in FIGS. 9A and 9B are each four, but may be three or less, and the contents are not limited to those shown. .

FIG. 10 is a timing chart of each signal when a jam occurs. When the CPU 601 detects the occurrence of a jam, a predetermined time width (100
ms). At the same time, code 0 signal 72
As the 2 and code 1 signal 723, a numerical value representing the type of the jam is output. In the example of FIG. 10, code 0 = ”
H ”and code 1 =“ L. ”The CPU 701 constantly and periodically (every 20 ms) outputs the jam occurrence signal 725.
Is checked, and when it is detected that the level has changed from "L" to "H", the levels of code 0 and code 1 at that time are read. In the example of FIG.
= "H", code 1 = "L" (that is, paper discharge sensor jam). Thus, the main body 700
The CPU 701 on the side recognizes the type of the jam that has occurred, and can perform processing according to the type of the jam.

FIG. 11 is a timing chart of each signal when the document size is notified. The CPU 701 sets the document feed request signal 7
21 occurs at time t21, and AF6
00 feeds one new document. When the paper feeding is completed,
The CPU 601 generates a pulse having a predetermined time width (100 ms) as the paper feed completion report signal 724 (time t2).
2). At the same time, a numerical value representing the size of the fed document is output as a code 0 signal 722 and a code 1 signal 723. The detection of the size can be performed by any known method. For example, the size in the direction perpendicular to the document conveyance direction can be detected by the document width sensor described above. Alternatively, it can be detected according to the position of the document guide of the document insertion port 23 as shown in FIGS. The size of the document in the transport direction can be obtained based on the count value by counting the number of output pulses applied to the document transport motor while the sensor (for example, the image sensor S3) is on. In the example of FIG. 11, code 0 = "L" and code 1 = "H" (that is, A
4S). The CPU 701 constantly and periodically (every 20 ms) checks the paper feed completion report signal 724, and when it detects that the level has changed from “L” to “H”, the code 0 signal 722 and the The level of the code 1 signal 723 is read. In this way, the CPU 701 recognizes the size of the fed document,
The corresponding copy paper can be automatically selected and fed.

FIG. 12 shows a specific example of the main body initialization processing executed when the power of the copier main body 700 is turned on. In this example, first, the flag F0, the variable i, and the variable pc are initialized to 0 (S121), and then the interval timer for the CPU 701 is turned on (S122). When the interval timer is turned on, the processing of FIG. 14 is thereafter executed periodically (every 20 ms).

FIG. 13 shows a specific example of the initialization processing of the AF 600. In this example, first, the flag F1 is initialized to 0 (S131).
The F version number (binary number) is read (S132).
It waits until a predetermined time (600 ms) elapses after the power is turned on (S133), outputs a synchronization signal to the code 0 signal 722, and, in synchronization with this, serially outputs the version number to the code 1 signal 723 (S134). Thereafter, the interval timer for the CPU 601 is turned on (S135). By turning on the interval timer, the processing of FIG. 15 described later is periodically (20 ms).
Every time).

Referring to FIG. 14, a specific example of the periodic operation executed by the main body side CPU 701 will be described. This process is started in a cycle of 20 ms in this example.

First, it is checked whether the flag F0 is 0 (S
1401). If F0 is not 0, step S described later
Branch to 1412. This flag F0 is initialized to "0" immediately after the power is turned on (S121 in FIG. 12), and becomes "1" when the transmission process of the version number executed thereafter is completed. By this flag F0,
The processing immediately after turning on the power is separated from the subsequent normal processing.

When F0 = 0, that is, immediately after the power is turned on, the time since the power is turned on is counted (S1402).
This processing is immediately terminated until a predetermined time (600 ms) elapses (S1403). About 30
After repeating the predetermined time, the predetermined time elapses, and step S
Go to 1404. In this step, the value of the code 0 signal 722 is taken into the variable nc (S1404). Then
The value of the variable nc is compared with the value of the variable pc (S140)
5). The initial value of the variable pc is “0” as set in step S121 in FIG. Therefore, first, when "1" is taken into nc in step S1404, a mismatch occurs in step S1405. That is, a change in code 0 (in this case, a synchronization signal) is detected. Until the change of code 0 is detected, the present process is terminated at that point.

When a mismatch between nc and pc is detected in step 1405, the nc value is set as a new pc value in preparation for the detection of a subsequent change in the code 0 signal (S140).
6).

Next, the variable i indicating the bit number is incremented (S1407). This variable i is initially initialized to “0” in step S121 of FIG.
If the value of the variable i after the increment exceeds “8”, the transmission process of the version number has been completed, so the flag F0 is set to 1 (S1409), and the process proceeds to the subsequent step S1409.

In step S1408, the value of the variable i is "8".
In the following case, the value of the code 1 signal at that time is
(S1410), and this is substituted for the array b (i) (S1411). Thus, the present processing is ended.

Steps 1404 to 1411 are repeated eight times every 20 ms, and the 8-bit version number is stored in the array b.
(I), the transmission of the version number is completed. After the transmission of the version number is completed, the flag F0 = 1, so that the process jumps from step S1401 to step S1412, and the execution of steps S1404 to S1411 is omitted.

At step 1412, the jam occurrence signal 7
It is checked whether or not 25 has changed from the off state to the on state. If the change to the ON state is detected, the values of code 0 and code 1 are substituted for variables J (0) and J (1) representing the type of jam (S141).
5).

In step S1412, the jam occurrence signal 72
5 is not detected, the paper feed completion report signal 7
It is checked whether or not 24 has changed from the off state to the on state (S1413). If the result is No, the process ends. If the result is Yes, the variable S representing the document size is set.
(0) and S (1) have code 0 and code 1 respectively.
Is substituted (S1414).

Next, referring to FIG. 15, the AF-side CPU 601 will be described.
The following describes a specific example of the periodic operation performed by. This processing is also started in a cycle of 20 ms in this example.

First, it is checked whether or not a new document jam has occurred in the document feeding operation based on the outputs of various sensors (S1501). If a jam has not been detected, the flow shifts to step S1505 described later.
If the occurrence of a jam is detected, the type of the jam is confirmed (S1502). Next, the jam occurrence signal 72
5 is output (S1503). Further, a value corresponding to the jam type is output to the code 0 signal 722 and the code 1 signal 723 (S1504), and the process ends.

If no jam has been detected in step S1501, it is checked whether the document feed request signal 721 has changed to the ON state (S1505). If it is not detected that the state has changed to the ON state, the process proceeds to step S1508. If it is detected that the state has changed to the ON state, the document feeding unit 607 is instructed to start feeding a new document (S1506). Next, the flag F1 is set to 1 (S1507). The flag F1 is a flag that remains "1" after a document feed request is generated until the document feed is completed in response to the request. Next, the value of the flag F1 is checked (S1508). If F = 1, the document feeding request has not been processed, and it is checked whether the feeding has been completed (S1509). When the paper feeding is completed, a pulse is output as the paper feeding completion report signal 724 (S1510). And,
A value indicating the document size is output to the code 0 signal 722 and the code 1 signal 723 (S1511). Step S
If F = 0 in 1508, the document feed request is not in a valid state, and therefore, it is checked in step S1509 whether the feed has been completed.
The execution of S1510 is omitted.

Although the preferred embodiment of the present invention has been described above, various modifications and changes are possible. For example,
Although the version number is 8 bits, the version number may be any number of bits other than 8 bits. In addition, 20ms, 10
Specific times such as 0 ms and 600 ms are merely examples, and the present invention is not limited to these.
In the above embodiment, the DF is controlled on the main body side, but may be controlled from the AF side. Furthermore, A
The present invention can also be applied to a case in which F is not provided and a CPU other than the CPU of the main body is provided in the DF.

[0056]

According to the present invention, communication between the image forming apparatus main body and the document feeder can be performed with a simpler hardware configuration.

[0057]

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a copying machine to which the present invention is applied.

FIG. 2 is an explanatory diagram of an example of use of a document feeder (DF) of the copying machine of FIG. 1;

3 is an explanatory diagram of an example of use in a case where an automatic document feeder (AF) is attached to the document feeder (DF) of the copying machine of FIG. 1;

FIG. 4 is a schematic diagram showing a relationship between respective sections inside the document feeder shown in FIG. 1;

FIG. 5 is a sectional view showing a schematic structure inside the copying machine of FIG. 1;

FIG. 6 is a block diagram showing a hardware configuration inside the copying machine of FIG. 1;

FIG. 7 is an explanatory diagram showing an interface between the copying machine main body shown in FIG. 6 and an automatic document feeder (AF).

FIG. 8 is a timing chart for explaining an operation at the time of a version signal notification according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram for describing the operation contents when a jam occurs (a) and when a document size is notified (b) according to the embodiment of the present invention.

FIG. 10 is a timing chart for explaining an operation when a jam occurs in the embodiment of the present invention.

FIG. 11 is a timing chart for explaining an operation at the time of notification of a document size according to the embodiment of the present invention.

FIG. 12 is a flowchart illustrating initialization processing of the copying machine main body according to the present embodiment.

FIG. 13 shows an automatic document feeder (A
It is a flowchart which shows the initialization process of F).

FIG. 14 is a flowchart showing a periodic process of a copying machine main body side CPU in the present embodiment.

FIG. 15 is a flowchart illustrating periodic processing of an AF-side CPU according to the present embodiment.

[Explanation of symbols]

11 Document transport belt, 12 Operation panel, 13 Front tray, 15 Document discharge tray, 23 Document insertion slot, 24, 25 Pulley, 26 Path switching claw, 27 Paper discharge path, 28 Discharge Paper rollers, 30 guides, 32 document discharge trays, 61 document feeders (covers), 62 platen glasses, 63 developing devices, 64 reading optical systems,
65: photosensitive drum, 68: fixing device, 70: copy discharge tray, 74: manual feed tray, 100: copying machine, 600:
Automatic document feeder (AF), 601, CPU, 700,
Copier body, 701: CPU, S1: Document input sensor,
S2: paper feed sensor, S3: image sensor.

Claims (9)

[Claims] An image forming apparatus having a document feeder, wherein the image forming apparatus main body has a first CPU, and the document feeder has a second CPU; Are connected by first and second signal lines, and the second CPU outputs a synchronization signal that is turned on and off at a constant period on the first signal line when the power of the image forming apparatus is turned on. And outputting serial data in synchronization with the synchronization signal on the second signal line, wherein the first CPU periodically monitors the synchronization signal on the first signal line and monitors a change in the synchronization signal. At each point detected,
An image forming apparatus with a document feeder, wherein the serial data is recognized by confirming a signal level of the serial data on the second signal line. 2. The image forming apparatus with a document feeder according to claim 1, wherein said serial data is a version number of said document feeder. 3. The image forming apparatus with a document feeder according to claim 1, wherein said first and second signal lines are shared for transmitting data different from said serial data. 4. The first and second CPUs are further connected by a third signal line, and the second CPU receives the third signal every time the feeding of one document is completed. A pulse signal indicating a paper-supply completion report is output on the signal line, and the size data of the document whose paper-supply is completed is output on the first and second signal lines. 3 is periodically monitored, and when the generation of the pulse signal is detected, the signal level of the size data on the first and second signal lines is checked, whereby the size of the original document is reduced. 4. The image forming apparatus with a document feeder according to claim 3, wherein the image forming apparatus recognizes the document. 5. The image processing apparatus according to claim 1, wherein the first and second CPUs are further connected by a fourth signal line, and the second CPU detects the occurrence of a jam when feeding a document. And a pulse signal indicating the occurrence of a jam is output on the first signal line, and the type data of the jam is output on the first and second signal lines. The first CPU outputs a signal on the fourth signal line. The level is periodically monitored, and when the occurrence of the pulse signal is detected, the type of the jam is recognized by confirming the signal level of the jam type data on the first and second signal lines. The image forming apparatus with a document feeder according to claim 3 or 4. 6. The first and second CPUs are further connected by a fifth signal line, wherein the first CPU is connected to the second CPU when document feeding is required. Outputting a document feed request signal on the fifth signal line, the second CPU responding to the document feed request signal from the first CPU output on the fifth signal line,
5. The image forming apparatus with a document feeder according to claim 1, wherein the document is fed. 7. A method for performing communication between an image forming apparatus main body having a CPU and a document feeder, comprising:
Outputs a synchronizing signal that is turned on and off at regular intervals from a first output terminal thereof to a first signal line connected to a first input terminal of the main body side CPU,
Outputting serial data in synchronization with the synchronizing signal from a second output terminal of the PU to a second signal line connected to a second input terminal of the main body side CPU; The synchronization signal on the line is periodically monitored, and when a change in the synchronization signal is detected, the second
A method for recognizing the serial data by confirming a signal level of the serial data on a signal line of the image forming apparatus. 8. The CPU of the document feeder switches from a third output terminal of the CPU of the document feeder to a third input terminal of the CPU of the main body every time the feeding of one document is completed. A pulse signal indicating a paper feed completion report is output on the connected third signal line, and the first paper source CPU of the document feeder side CPU
And outputting, from the second output terminal, the size data of the fed document to the first and second signal lines, and the main body side CPU periodically monitors the signal level on the third signal line. Wherein the generation of a pulse signal is detected, the signal level of the size data on the first and second signal lines is confirmed to recognize the document size of the document. The data communication method according to claim 7, wherein the data communication method is performed in a forming apparatus. 9. The document feeder-side CPU detects the occurrence of a jam when feeding a document, and detects a document feeder-side CPU.
A pulse signal indicating the occurrence of a jam is output from a fourth output terminal of the CPU to a fourth signal line connected to a fourth input terminal of the CPU of the main body. 2 outputs the type data of the jam on the first and second signal lines from the output terminal of the second signal line, and the main body side CPU periodically monitors the signal level on the fourth signal line to generate a pulse signal. 8. The image forming apparatus with a document feeder according to claim 7, wherein when detected, the type of the jam is recognized by confirming the signal level of the jam type data on the first and second signal lines. Or the data communication method according to 8.