Image forming apparatus and sheet processing apparatus with a serial connection

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming apparatus and a sheet processing apparatus that perform serial communication with one another.

2. Description of the Related Art

Conventionally, serial communication is normally used for communication between an image forming apparatus and a sheet processing apparatus (finisher). In this case, three-wire serial communication is used between the conventional image forming apparatus and the finisher, with a controller (ECONT) for controlling image forming operations by the image forming apparatus on the master side. The three-wire serial communication lines are composed of a serial communication line from the image forming apparatus to the finisher, a serial communication line from the finisher to the image forming apparatus, and a clock signal line for serial communication from the image forming apparatus to the finisher. When there are signals that cannot be handled by such three-wire serial communication, other communication lines are separately provided between the image forming apparatus and the finisher.

A finisher is usually designed as an option to be connected to an image forming apparatus, so that the image forming apparatus needs to determine whether a finisher has been provided. A configuration where the image forming apparatus is provided with separate signal lines for determining whether options have been connected is conventionally known, though this means that in addition to the three-wire serial communication lines described above, extra signal lines have to be provided for detecting options. Increasing the number of signal lines leads to increases in the cost of the connectors that connect the cables between the image forming apparatus and the finisher. Also, for ease of mounting, a number of connectors are used to connect the cables between the image forming apparatus and the finisher, so that increases in the cost per connector cannot be ignored for the apparatus as a whole. Furthermore, there is a tendency for the amount of noise, which is radiated from serial communication lines due to the antenna effect of the signal lines, to increase in keeping with the number of signal lines. It is also necessary to provide a CPU of the image forming apparatus with a port for inputting signals from the signal lines for detecting options, which suppresses the freedom with which the ports can be used for the CPU even though the CPU itself is often subject to restrictions regarding the number of ports.

A configuration is known where predetermined communication for device detection is performed between the image forming apparatus and optional devices so that the image forming apparatus can judge whether options are provided, though with this configuration the image forming apparatus cannot judge instantly whether options are provided. Conventionally, it is judged whether options have been provided every time the power of the image forming apparatus is switched on, though since the starting up of the image forming apparatus itself takes time, the communication time taken to judge whether options are provided has not been a problem compared to the time taken by the starting up of the image forming apparatus. However, in recent years, to reduce power consumption, image forming apparatuses have been designed so as to frequently switch to power saving mode and the startup time of image forming apparatuses has been reduced. Since it is necessary to detect whether options are connected whenever an image forming apparatus returns from power saving mode, if an image forming apparatus judges whether options are attached by communicating with the options in the conventional manner, it is not possible for the image forming apparatus to quickly start up from the power-saving mode.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the above described problem, and it is an object of the present invention to provide a sheet processing apparatus and an image forming apparatus, which make it possible to determine whether the sheet processing apparatus is attached to the image forming apparatus in a short time and without increasing the number of signal lines.

To attain the above object, in a first aspect of the present invention, there is provided a sheet processing apparatus to be attached to an image forming apparatus, comprising a controller that controls the sheet processing apparatus, and a serial communication line that performs serial communication from the controller to the image forming apparatus, wherein the controller is responsive to supplying of power to the controller, for setting the serial communication line at a high level.

In a preferred form, the sheet processing apparatus according to the first aspect comprises a resistor, and a first switching element, and wherein the serial communication line is disposed such that a voltage is applied to the serial communication line via the resistance, the serial communication line is grounded via the first switching element, and the controller controls the first switching element.

Preferably, the controller sets the serial communication line at the high level by turning off the first switching element.

More preferably, the controller performs serial communication with the image forming apparatus by turning the first switching element on and off.

Preferably, the first switching element comprises a transistor.

Also preferably, the serial communication line is disposed relative to the image forming apparatus such that a voltage of a power supply supplied by the image forming apparatus is applied to the serial communication line via the resistance.

Further preferably, the sheet processing apparatus according to the first aspect comprises a second switching element, and wherein power supplied from the image forming apparatus is supplied to the controller and the serial communication line via the second switching element, and wherein the second switching element is controlled in accordance with a signal on a power supply control signal line from the image forming apparatus.

Advantageously, the second switching element comprises a field effect transistor (FET).

Also advantageously, the sheet processing apparatus according to the first aspect further comprises a second serial communication line that performs serial communication from the image forming apparatus to the controller.

Preferably, the image forming apparatus is responsive to supplying of the power to the controller, for determining whether the serial communication line is at the high level, and determines that the sheet processing apparatus is attached when the serial communication line is at the high level.

Also preferably, the image forming apparatus judges whether the serial communication line is at the high level after a predetermined time period has passed after the power has been supplied to the controller.

To attain the above object, in a second aspect of the present invention, there is also provided an image forming apparatus to which the above described sheet processing apparatus is attached, the image forming apparatus comprising a second controller that controls the image forming apparatus, wherein the serial communication line performs serial communication from the sheet processing apparatus to the second controller, and wherein the second controller is responsive to supplying of power to the sheet processing apparatus, for determining whether the serial communication line is at a high level, and determines that the sheet processing apparatus is attached when the second serial communication line is at the high level.

Preferably, the second controller determines whether the serial communication line is at the high level after a predetermined time period has passed after the power has been supplied to the sheet processing apparatus.

Also preferably, the image forming apparatus according to the second aspect comprises a power supply control signal line, and wherein the second controller controls supplying of the power to the sheet processing apparatus via the power supply control signal line, and wherein the second controller determines whether the serial communication line is at the high level after instructing the supplying of the power to the sheet processing apparatus via the power supply control signal line.

More preferably, upon returning from a power saving mode, the second controller instructs the supplying of the power to the sheet processing apparatus via the power supply control signal line and then determines whether the serial communication line is at the high level.

Advantageously, the image forming apparatus according to the second aspect further comprises a second serial communication line that performs serial communication from the second controller to the sheet processing apparatus.

The above and other objects, features and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a cross-sectional view of an image forming apparatus and a finisher according to an embodiment of the present invention;

FIG. 2

is a block diagram showing the overall construction of the image forming apparatus and option devices;

FIG. 3

is a block diagram showing the construction of an IP

9

of the image forming apparatus and its related components;

FIG. 4

is a block diagram showing the construction of an ECONT

19

of the image forming apparatus and its related components;

FIG. 5

is a block diagram for the control of the finisher

23

according to the embodiment of the present invention;

FIG. 6

is a block diagram of the arrangement of components of the image forming apparatus

500

for the control of the apparatus according to the embodiment of the present invention;

FIG. 7

is a diagram showing the procedure by which the image forming apparatus judges whether the finisher is attached;

FIG. 8

is a diagram showing the procedure by which the image forming apparatus judges whether the finisher is in an abnormal state;

FIG. 9

is also a diagram showing the procedure by which the image forming apparatus judges whether the finisher is in an abnormal state;

FIG. 10

is a flowchart showing the operation of the image forming apparatus;

FIG. 11

is a continued part of the

FIG. 10

flow chart;

FIG. 12

is a block diagram of the arrangement of components for the control of a finisher

23

according to another embodiment of the present invention; and

FIG. 13

is a block diagram of the arrangement of components for the control of an image forming apparatus

500

according to the other embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As a sheet processing apparatus which is connected to an image forming apparatus, aside from a finisher that stacks recording sheets, shifts recording sheets, or staples recording sheets together, as used in embodiments of the present invention, the present invention can also be effectively applied to an accessory apparatus, such as a sorter that sorts recording sheets, and a filing apparatus that gathers and files a plurality of recording sheets, which is connected to the discharge system of an image forming apparatus. The present invention can also be effectively applied to an interface for an accessory that is equipped with a high performance CPU. Further, in the embodiments described below, a paper-full detecting sensor for detecting whether a discharge tray is full of recording sheets is removed when the finisher is attached to the image forming apparatus, and it is determined that the discharge tray is full of recording sheets in accordance with special logic that is set in advance for the case where the paper-full detecting sensor has been removed, and control is provided such that recording sheets are not discharged to the finisher. However, it may be constructed such that a controller of the image forming apparatus performs control such that recording sheets are not discharged to a finisher when the sensor is removed and the detection as to whether the discharge tray is full of recording sheets is not carried out when the finisher has been attached to the image forming apparatus.

The present invention will now be described in detail with reference to the accompanying drawings showing preferred embodiments thereof.

FIG. 1

is a diagram showing the construction of an image forming apparatus equipped with a finisher according to an embodiment of the present invention. In the figure, reference numeral

500

designates the image forming apparatus. The image forming apparatus

500

includes an image reader

200

and a printer

300

, and is also equipped with a finisher

23

that is disposed between the image reader

200

and the printer

300

that is an image forming unit.

The image reader

200

is provided with a scanner unit

182

and an automatic original feeder

2

, with the automatic original feeder

2

separating one sheet at a time in order from a top of original sheets that have been set face up and feeding the original sheet leftwards so as to convey the sheet via a curved path onto a platen glass

181

while also discharging original sheets that have been read onto a discharge tray

112

.

The scanner unit

182

is provided with a lamp

183

that emits light onto an original that has been conveyed onto the platen glass

181

, and once the light emitted onto the original by the lamp

183

has been reflected off the sheet, an image of the original is read by a contact sensor

8

.

On the other hand, the printer

300

is equipped with a laser unit

808

for outputting laser light in accordance with an original image that has been read by the contact sensor

8

and subjected to image processing. The laser light emitted by the laser unit

808

strikes a photosensitive drum

111

and forms an electrostatic latent image on the photosensitive drum

111

. After this, the electrostatic latent image on the photosensitive drum

111

is developed by a developer

113

to become a toner image, and this toner image is transferred by a transfer unit

116

onto a sheet that has been fed from any of sheet feed cassettes

114

,

115

, a manual sheet feed unit

125

, or a two-sided conveying path

124

.

It should be noted that when a sheet onto which a toner image has been transferred in this way passes a fixing unit

117

, the sheet is subjected to a fixing process and is guided past the fixing unit

117

to discharge rollers

118

, which discharge the sheet from the printer

300

with the transferred toner image-formed surface facing downwards (i.e., the sheet is discharged face down). By discharging sheets in a face-down manner in this way, when image formation is preformed in order starting from the first page, such as when the automatic original feeder

2

is used or when images outputted by a computer are printed, the discharged recording sheets are arranged in the correct order. It should be noted that when two-sided image forming is performed, a sheet that passes the fixing unit

117

is guided to a discharge path

122

by a flapper

121

, and switched back and guided to the two-sided conveying path

124

, with an image then being formed on the back of the sheet by the operation described above.

On the other hand, the sheets that have been discharged in this way by the discharge rollers

118

are fed into the finisher

23

. It should be noted that in the present embodiment, the finisher

23

is a device that performs a stapling (binding) operation on sheets.

The sheets received from the printer

300

are fed via a path

416

to discharge rollers

415

, with the discharge rollers

415

then discharging the sheets onto a slanted bundle discharge belt

421

. After the sheets have been discharged onto a low-friction intermediate processing tray that is a sheet gathering means (not shown in the figure), the bundle discharge belt

421

discharges the sheets (bundle) that have been subjected to a stapling process by a stapling unit

917

. It should be noted that the intermediate processing tray is disposed parallel with and several millimeters higher than the bundle discharge belt

421

.

The bundle discharge belt

421

includes a bundle discharge lever

421

A and when the bundle discharge belt

421

rotates, the bundle of sheets that has been subjected to the stapling process is pushed in the right upward direction by the bundle discharge lever

421

A so as to be discharged onto a stack tray

411

that has moved to a predetermined loading position. It should be noted that the stack tray

411

can rise and fall in accordance with the loaded amount of sheets.

In

FIG. 1

, reference numeral

417

designates a fan-shaped return roller that is a first matching means. The return roller

417

rotates and comes into contact with the sheets discharged onto the intermediate processing tray, so as to move the sheets in the left downward direction. Reference numeral

412

indicates matching plates that form a second matching means for lining up both side edges of the sheets on the intermediate processing tray, with the plates being disposed at near and far locations in the depth direction of FIG.

1

.

FIG. 2

is a block diagram showing the overall construction of the image forming apparatus

500

and option devices according to the present embodiment. In

FIG. 2

, reference numeral

1

designates a power supply unit (PSU) that supplies a voltage to the image forming apparatus

500

and the option devices. Reference numeral

2

designates the automatic original feeder (ADF) that feeds a plurality of originals that have been set on the image forming apparatus

500

one sheet at a time to an original reading position on a platen. Reference numeral

3

designates a network control unit (NCU) that performs communication. Reference numeral

4

designates a BOOK unit that controls the reading of originals. Reference numeral

5

designates a modular jack (MJ)

5

for connection with networks. Reference numeral

6

designates a communication unit as an option device that performs simultaneous communication with two networks. Reference numeral

7

designates an image processing unit that processes images outputted by the contact sensor

8

.

Reference numeral

9

designates a controller (IP) that controls parts of the entire system (the image forming apparatus

500

and the option devices) aside from the image forming (recording) system, with a CPU

101

in charge of such control. Reference numeral

10

designates a serial counter that stores the number of sheets printed by the image forming apparatus

500

(which is a printer, a copier, or a multi-function apparatus). Reference numeral

11

designates an operation unit that is comprised of a display means, which displays a state of the image forming apparatus

500

to the user, and a key input means, which the user operates to determine the operation of the image forming apparatus

500

. Reference numeral

12

designates a page description language (PDL) processing unit, or in other words, a formatter, that, for example, converts character codes that have been received from an external device via a network into image data that can be printed by the image forming apparatus

500

.

Reference numeral

13

designates a hard disk drive that is used for loading and storing data that has been received from an external device via a network. Reference numeral

14

designates a network interface card (NIC) that provides an interface with a network. Reference numeral

15

designates an ECO-ID card that includes a storage medium that stores information from the serial counter

10

on the outside to thereby protect any loss in the number of sheets printed by the image forming apparatus

500

(a printer, copier, or multi-function apparatus) due to tampering or the like. Reference numeral

16

designates a maintenance communication unit that exchanges maintenance information with the image forming apparatus

500

via a card or a public telephone line. Reference numeral

17

designates a card reader that can read management information from a detachable card that stores management information used in the case where the image forming apparatus

500

is managed separately for each department in an enterprise, for example.

Reference numeral

18

designates a scanner unit that reads an original image in order for an image to be formed on the photosensitive drum

111

. Reference numeral

19

designates a controller (ECONT) that controls image formation (recording), with a CPU

102

in charge of such control. Reference numeral

20

designates a high-voltage unit that produces a high voltage signal for having toner applied onto the photosensitive drum

111

in accordance with the formed (recorded) image and transferring the toner image onto a recording sheet. Reference numeral

21

designates a fixing heater unit that is provided with the fixing unit

117

for fixing the toner that is attached to the recording sheet using heat and pressure. It should be noted that the developing system, transfer system, fixing system, etc., including the photosensitive drum

111

, constitute the image forming unit. Reference numeral

22

designates an inner discharge tray that is optionally provided for sorting recording sheets onto which images have been formed (recorded). Reference numeral

23

designates a recording sheet processing device (finisher) that can be detachably attached to the image forming apparatus

500

, and is controlled by a CPU

103

. Reference numeral

24

designates an option feeder that can be attached as an option to the image forming apparatus

500

provided that the finisher

23

is not attached at the same time. Reference numeral

25

designates a network control unit (NCU) for a second network.

FIG. 3

is a block diagram showing the construction of the controller IP

9

of the image forming apparatus and its related components for controlling the entire system comprised of the image forming apparatus

500

and option devices according to this present embodiment. It should be noted that elements and parts of

FIG. 3

that are the same as in

FIG. 2

are designated by identical reference numerals and description thereof is omitted. In

FIG. 3

, reference numeral

30

to

32

are original length sensors for detecting the length of the originals on the ADF

2

. Reference numeral

33

designates a thermistor for detecting the temperature at a predetermined location. Reference numeral

34

designates an original feeding motor for feeding originals that are set on the ADF

2

. Reference numeral

35

designates a confirmation stamp that is pressed onto fax originals that have been transmitted from this image forming apparatus

500

to an external device. Reference numeral

36

designates a cover sensor for detecting whether the cover for setting originals on the ADF

2

is open. Reference numeral

37

designates an original edge sensor for detecting an edge of an original, and is disposed just before the original reading unit.

Reference numeral

38

designates a clutch for pulling originals towards a reading position. Reference numeral

39

designates an ADF driver for driving the ADF

2

. Reference numeral

40

designates a motor driver for driving the original feeding motor

34

. Reference numeral

41

designates a sensor baseplate on which various sensors

42

to

45

are mounted. Reference numerals

42

and

43

designate original width sensors for detecting the width of originals. Reference numeral

44

designates an original sensor for detecting whether there is an original on the ADF

2

. Reference numeral

45

designates a sensor that is disposed between the original sensor

44

and the original edge sensor

37

and is used for measuring timing in which the original reading unit is driven. Reference numerals

50

,

51

designate sensors for detecting, when a pressing plate for pressing the original or an ADF

2

for feeding originals is present on the platen, whether the pressing plate or ADF

2

has been opened.

Reference numeral

52

designates a home position sensor for detecting whether the contact sensor (CS)

8

is in a home position thereof. Reference numeral

53

designates a CS driving motor for driving the CS

8

. Reference numerals

54

to

57

designate sensors for detecting the size of an original placed on the platen in the case where the states of the sensor

50

and the sensor

51

show that the pressing plate or the ADF

2

has been opened by a certain degree. Reference numeral

58

designates a motor driver for driving the CS driving motor

53

. Reference numeral

59

designates an EEPROM that is a memory element of the serial counter

10

. Reference numeral

60

designates an EEPROM that is a memory element of the ECO-ID card

15

. Reference numeral

61

designates a ROM for deciding the operation of the IP

9

. Reference numerals

62

,

63

designate expansion RAMs for storing image signals and the like. Reference numeral

64

designates a speaker for emitting sounds. Reference numeral

65

designates a differential amplifier for sending print video data to the ECONT

19

. Reference numeral

66

designates a differential amplifier for receiving print video data from the PDL processing unit

12

. Reference numeral

103

designates the CPU of the IP

9

.

FIG. 4

is a block diagram showing the construction of the controller (ECONT)

19

, which controls image forming operations by the image forming apparatus

500

according to the present embodiment, and electronic components in the periphery of the ECONT

19

. It should be noted that elements and parts that are the same as in

FIGS. 2 and 3

are designated by reference numerals and description thereof is omitted. In

FIG. 4

, reference numeral

803

is a pre-resist sensor for detecting that the recording sheet is just before the photosensitive drum. Reference numeral

804

designates a main motor for driving the entire image forming (recording) unit. Reference numeral

805

designates a manual paper feed solenoid for picking up a recording sheet that is inserted from the manual sheet feed unit

125

. Reference numeral

806

designates a resist clutch for pulling paper, when the paper is caught on the pre-resist sensor

803

, so as to flex the paper by a certain degree. Reference numeral

807

designates a fan motor for circulating air in order to lower the temperature of mechanisms that emit heat inside the image forming apparatus

500

.

Reference numeral

808

designates a laser unit for irradiating a laser beam onto the photosensitive drum. Reference numeral

809

designates a beam detection sensor for detecting the synchronization timing of the scanning of the laser in the horizontal direction. Reference numeral

810

designates a scanner motor for scanning the laser. Reference numeral

811

designates a paper size switch for detecting the size of the recording sheets stored in the sheet feed cassettes inside the image forming apparatus

500

. Reference numeral

812

designates a solenoid for picking up a recording sheet stored in one of the internal sheet feed cassettes

114

and

115

when paper is fed. Reference numeral

814

designates a retry sensor for detecting when a recording sheet picked up from the sheet feed cassette

114

or

115

has not reached a predetermined position and outputting a signal to the ECONT

19

for retrying the picking up of a recording sheet.

Reference numerals

815

and

816

designate door sensors for detecting when front doors provided in the image forming apparatus

500

for maintenance purposes are open. Reference numeral

24

designates a cassette feeder that is attached to the image forming apparatus

500

as an option. Reference numeral

23

designates a recording sheet processing apparatus (finisher) that can be detachably attached to the image forming apparatus

500

. Reference numeral

22

designates an inner discharge tray that is attached to the image forming apparatus

500

as an option. Reference numeral

820

designates a discharge sensor for detecting whether a recording sheet has been discharged. Reference numerals

821

and

822

designate thermistors for detecting the temperature of the fixing heater unit

21

. Reference numeral

823

designates a paper-full detecting sensor that is disposed downstream of the recording sheet discharging system and when the finisher

23

is not attached to the image forming apparatus

500

, detects whether the discharge tray is full of recording sheets. The paper-full detecting sensor

823

is removed when the finisher

23

is attached to the image forming apparatus

500

. Reference numeral

824

designates a sensor for detecting whether a recording sheet or sheets are present on the manual sheet feed unit. Reference numeral

825

is a used toner full detection sensor for detecting whether a used toner vessel is full. Reference numeral

102

designates the CPU of the ECONT

19

.

FIG. 5

is a block diagram showing the construction of the finisher

23

that can be detachably attached to the image forming apparatus

500

according to the present embodiment. In

FIG. 5

, reference numeral

901

designates an interface for transmitting and receiving a variety of signals between the finisher

23

and the image forming apparatus

500

. Reference numeral

103

designates the CPU that controls the various parts of the finisher

23

. Reference numeral

903

designates a plurality of photosensors provided within the finisher

23

, for performing various detections. Reference numeral

904

designates a field effect transistor (FET) that is disposed between the CPU

103

and various drivers, described below, and the interface

901

, with a FOFF signal from the image forming apparatus

500

being inputted to the FET

904

via the interface

901

. Reference numeral

905

designates a fuse for limiting the electric current. Reference numeral

906

designates a circuit breaker for limiting the electric current.

The interface

901

serves as an interface for an SI signal, an SO signal, an SCK signal, FCCRT, FBUSY, and an FOFF signal. The SI signal is for serial communication from the CPU

103

to CPU

102

, while the SO signal is for serial communication from the CPU

102

to CPU

103

. The SCK signal is a clock for the serial communication performed using the SI signal and the SO signal. FCCRT designates a signal expressing whether or not there is information from the finisher

23

. FBUSY designates a signal expressing whether the CPU

103

is capable of communication. The FOFF signal is a signal for switching the FET

904

on and off. Also, a 5V supply and a 24V supply are provided to the finisher

23

via the interface

901

.

When the FOFF signal is on, the FET

904

provides the 5V supply provided via the interface

901

and the fuse

905

to the CPU

103

, a resistor

919

, a driver

908

, a driver

910

, a driver

912

, a driver

914

, a driver

916

, and a driver

918

. The CPU

103

, when provided with the 5V supply from the FET

904

, turns the transistor

920

off. When the transistor

920

is turned off, the voltage of the SI signal is set at a high level. That is, when the 5V supply is provided from the FET

904

, the CPU

103

pulls up the SI signal to a high level.

Accordingly, after the FOFF signal has switched from off to on, the CPU

102

that controls the image forming apparatus

500

can instantly detect whether the finisher

23

has been attached to the image forming apparatus

500

by judging whether the SI signal is at the high level. This is to say, after the FOFF signal has switched from off to on, the CPU

102

judges that the finisher

23

is attached to the image forming apparatus

500

when the SI signal is at the high level and that the finisher

23

is not attached to the image forming apparatus

500

when the SI signal is at the low level. It should be noted that after judging from the level of the SI signal that the finisher

23

is attached, the CPU

102

receives serial communication from the CPU

103

from the SI signal.

With this arrangement, there is the advantage that there is no need to provide the interface

901

with a line for judging whether the finisher

23

is attached. Since the number of lines in the interface

901

is thus prevented from increasing, more inexpensive connectors can be used as the interface

901

. When the finisher is implemented as an actual product, the CPU

102

and the CPU

103

are connected via a plurality of connectors, and therefore, even if the reduction in the cost per connector is smaller, this leads to a large reduction in the cost per apparatus. Also, the number of signal lines that generate antenna effects is reduced by the reduction in the number of communication lines between the CPU

102

and the CPU

103

, so that there is a further advantage in that increases in noise from the communication lines can be decreased. There is also no need to provide the CPU

102

with a port for judging whether the finisher

23

is attached, so that part of the limited number of ports that are provided on the CPU can be assigned to other functions.

Since a response from the CPU

103

to a communication from the CPU

102

is not required in order to judge whether the finisher

23

is attached, whenever necessary the CPU

102

can instantly judge whether the finisher

23

is attached. As a result, when the image forming apparatus

500

is started from power saving mode, the image forming control, which is performed in accordance with the attachment state of the finisher

23

, can be commenced in a short time.

Reference numeral

907

designates a stack tray motor for raising and lowering the stack tray

411

. Reference numeral

908

designates a driver IC for driving the stack tray motor

907

. Reference numeral

909

designates a discharge motor for driving the discharge rollers

415

that pulls a recording sheet, which has been discharged from the image forming apparatus

500

, into the finisher

23

and conveys the recording sheet towards the bundle discharge belt

421

(the intermediate processing tray). Reference numeral

910

designates a driver IC for driving the discharge motor

909

. Reference numeral

911

designates a bundle processing motor for driving the bundle discharge belt

421

. Reference numeral

912

designates a driver IC for driving the bundle processing motor

911

. Reference numeral

913

designates a front-matching motor for driving the inside matching plate

412

in order to align the recording sheets with the front limit. Reference numeral

914

designates a driver IC for driving the front-matching motor

913

. Reference numeral

915

designates a rear-matching motor for driving the nearside matching plate

412

in order to align the recording sheets with the rear limit. Reference numeral

916

designates a driver IC for driving the rear-matching motor

915

. Reference numeral

917

designates a stapling unit for stapling the recording sheets. Reference numeral

918

designates a driver IC for driving the stapling unit

917

.

FIG. 6

is a block diagram showing the construction of the image forming apparatus

500

according to the present embodiment. In

FIG. 6

, reference numeral

1001

designates an interface for transmitting and receiving a variety of signals between the finisher

23

and the image forming apparatus

500

. The interface

1001

serves as an interface for the SI signal, the SO signal, the SCK signal, FCCRT, FBUSY, and the FOFF signal described earlier. Reference numeral

102

designates the CPU that is in charge of the control of the various components of the image forming apparatus

500

. A 5V supply and a 24V supply are provided to the finisher

23

via the interface

1001

.

FIG. 7

is a block diagram showing how the finisher

23

is detected as being present and also the communication of the status of the finisher

23

between the ECONT

19

and the IP

9

after the finisher

23

has been switched on due to the power supply of the controller (ECONT

19

), which controls the image forming unit of the image forming apparatus

500

, being switched on by control of the controller (IP

9

), which controls the entire system comprised of the finisher

23

and the image forming apparatus

500

, and the FOFF signal having been switched on by the ECONT

19

. This control system is comprised of the CPU

101

of the IP

9

, the CPU

102

of the ECONT

19

, and the CPU

103

of the finisher

23

. The CPU

101

of the IP

9

is in charge of controlling the entire system comprised of the image forming apparatus

500

and the finisher

23

. The CPU

102

of the ECONT

19

is in charge of controlling the image forming unit (the developer system, the transfer system, and the fixing system). The CPU

103

of the finisher

23

is in charge of controlling the various parts of the finisher

23

.

First, (1) when the CPU

101

of the IP

9

transmits an instruction for turning on the power supply of the ECONT

19

to the CPU

102

of the ECONT

19

, the power supply of the ECONT

19

is turned on. Next, (2) the CPU

102

of the ECONT

19

transmits the FOFF signal to the CPU

103

of the finisher

23

to turn on the power supply of the finisher

23

. (3) When the CPU

103

of the finisher

23

has set the SI signal at the high level, the CPU

102

of the ECONT

19

regards the SI signal from the finisher

23

as an input in the timing in which the SI signal is set at the high level, and (4) after judging that the SI signal is at the high level, which indicates that the finisher

23

is present, the CPU

102

of the ECONT

19

sends back a status showing that the finisher

23

is present to the CPU

101

of the IP

9

. (5) Communication between the CPU

102

of the ECONT

19

and the CPU

103

of the finisher

23

then commences with the ECONT

19

as the master. (6) The CPU

101

of the IP

9

transmits a variety of commands relating to the finisher

23

to the CPU

102

of the ECONT

19

, and the CPU

102

of the ECONT

19

sends back the status of the finisher

23

to the CPU

101

of the IP

9

.

FIG. 8

is a block diagram showing how the ECONT

19

the ECONT

19

resets the power supply of the finisher

23

via the FOFF signal upon detection of an abnormal state of the finisher

23

, and switches the finisher

23

off when the finisher

23

remains in the abnormal state even after the power supply of the finisher

23

has been reset.

First, (1) when the CPU

102

of the ECONT

19

requests the CPU

103

of the finisher

23

to send the status of the CPU

103

, (2) the CPU

103

of the finisher

23

sends back an illegal state to the CPU

102

of the ECONT

19

. (3) Next, the CPU

102

of the ECONT

19

transmits the FOFF signal to the CPU

103

of the finisher

23

to reset the power supply of the finisher

23

, and (4) requests the CPU

103

of the finisher

23

to send the status of the CPU

103

. (5) If the CPU

103

of the finisher

23

transmits the illegal state to the CPU

102

of the ECONT

19

, (6) the CPU

102

of the ECONT

19

transmits the FOFF signal to the CPU

103

of the finisher

23

to switch off the power supply of the finisher

23

. On the other hand, the CPU

102

of the ECONT

19

sends back the state of the finisher

23

as the status to the CPU

101

of the IP

9

.

FIG. 9

is a block diagram showing how, even in the case where the finisher

23

is physically connected to the finisher

23

but the ECONT

19

judges that the finisher

23

is not present due to the electric circuits of the finisher

23

not operating normally, image formation (recording) is disabled based on a paper-full detection by the paper-full detecting sensor that is removed from the image forming apparatus

500

in order to connect the finisher

23

.

First, (1) when the CPU

101

of the IP

9

transmits an instruction for turning on the power supply of the ECONT

19

to the CPU

102

of the ECONT

19

, the power supply of the ECONT

19

is turned on. (2) Next, the CPU

102

of the ECONT

19

transmits the FOFF signal to the CPU

103

of the finisher

23

to turn on the power supply of the finisher

23

. After this, (3) due to an abnormality in the electric circuits of the finisher

23

, the CPU

103

of the finisher

23

sets the SI signal at the low level, that is, turns the transistor

920

off, the CPU

102

of the ECONT

19

regards the SI signal from the finisher

23

as an input in certain timing, and (4) after judging that the finisher

23

is not present, sends back a status of “the finisher

23

is absent” to the IP

9

. The CPU

101

of the IP

9

does not output recording data and by using a paper full detection signal from the paper full sensor that is removed from the image forming apparatus

500

in order to connect the finisher

23

, the CPU

102

of the ECONT

19

controls the image forming unit so as not to perform printing based on recording data.

The characteristics of the control performed by the CPU

101

of the controller (IP

9

) that controls the entire system composed of the image forming apparatus

500

and the finisher

23

according to this embodiment of the present invention, the CPU

102

of the controller (ECONT

19

) that controls the image forming part of the image forming apparatus

500

, and the CPU

103

of the finisher

23

for controlling the parts of the finisher

23

will be described below.

The CPU

102

of the ECONT

19

transmits and receives information (such as status information and commands) to and from the CPU

103

of the finisher

23

via three-wire serial communication lines, and also controls the power supply of the finisher

23

via the FOFF signal line.

When there has been an instruction for switching to power-saving mode from the CPU

101

of the IP

9

, the CPU

102

of the ECONT

19

turns off the high voltage system out of the high voltage system (24V supply) and the low voltage system (5V supply) of the image forming unit of the image forming apparatus

500

, in addition to performing control to turn off, via the FOFF signal line, the power supply of the finisher

23

, whose power consumption is relatively high.

The CPU

102

of the ECONT

19

also performs control to reset, via the FOFF signal line, a control system including the CPU

103

of the finisher

23

.

The CPU

101

of the IP

9

performs control to turn on and off the power supply of the CPU

102

of the ECONT

19

, the power supply of the electric components controlled by the CPU

102

of the ECONT

19

, and the electric components aside from the control system IC of the finisher

23

.

On judging from the communication with the CPU

103

of the finisher

23

that the finisher

23

is in an abnormal state, the CPU

102

of the ECONT

19

performs control via the FOFF signal line to reset the finisher

23

.

The CPU

103

of the finisher

23

pulls up the serial input signal as viewed from the ECONT

19

side, out of the three-wire serial communication signals. The CPU

102

of the ECONT

19

sets the FOFF signal at on after the ECONT

19

has been switched on. The power supply of the CPU

103

of the finisher

23

is reset after the control system IC of the finisher

23

is set at on via the FOFF signal and, after this resetting has released, the CPU

103

of the finisher

23

operates so that the level of the serial input signal becomes a high level as viewed from the ECONT

19

. The CPU

102

of the ECONT

19

defines the serial input signal as an input port after the power supply of the finisher

23

has been turned on by the FOFF signal, and by monitoring the input port in timing in which the signal level becomes high, performs control so as to judge that the finisher

23

is connected to the image forming apparatus

500

.

The CPU

102

of the ECONT

19

also communicates with the CPU

103

of the finisher

23

after confirming that the finisher

23

is connected to the image forming apparatus

500

, and performs control to inform the CPU

101

of the IP

9

of the connection of the finisher

23

to the image forming apparatus

500

and of the state of the finisher

23

.

When the paper-full detecting sensor (see FIG.

4

), which detects whether a discharge tray for recording sheets that have been discharged from the image forming apparatus

500

is full, has been removed from the image forming apparatus

500

in accordance with the connecting of the finisher

23

to the image forming apparatus

500

, even if it is judged that the finisher

23

is not connected due to the finisher

23

that has been connected to the image forming apparatus

500

not operating electrically due to an abnormality in the electrical circuits, the CPU

102

of the ECONT

19

still judges that the discharge tray is full of recording sheets in accordance with special logic that is set in advance for the case where the paper-full detecting sensor has been removed, and so performs control so that recording sheets are not discharged to the finisher

23

.

Next the operation of the image forming apparatus

500

according to the present embodiment constructed as above will be described in detail with reference to

FIGS. 10 and 11

.

FIGS. 10 and 11

are flowcharts showing the operation of the image forming apparatus

500

of the present embodiment. The process in these flowcharts is executed based on programs by the controller (IP)

9

that controls the entire system comprised of the image forming apparatus

500

and the finisher

23

and the controller (ECONT)

19

that controls the image forming unit of the image forming apparatus

500

.

In

FIG. 10

, the IP

9

first turns on the power supply of the ECONT

19

(step S1). The ECONT

19

sets the FOFF signal at on, and so turns on the power supply of the finisher

23

(step S2). Next, the ECONT

19

judges whether a predetermined time period has passed since the power supply of the finisher

23

was turned on (step S3). If the predetermined time period has not yet passed, the ECONT

19

performs other processing (step S6), while if the predetermined time period has passed, the ECONT

19

regards the SI signal outputted from the finisher

23

as an input port, and judges whether the finisher

23

is connected (as shown by a high level) to the image forming apparatus

500

(step S4). When the finisher

23

is connected to the image forming apparatus

500

, the process proceeds to step S5, while when the finisher

23

is not connected to the image forming apparatus

500

, the process proceeds to step S7.

When the finisher

23

is connected to the image forming apparatus

500

, the ECONT

19

sets the status sent back to the IP

9

as “finisher present”, redefines the SI signal as an input port, and commences communication with the finisher

23

. Also, the ECONT

19

sends back status information showing the state of the finisher

23

in accordance with the status reply received from the finisher

23

(step S5). On the other hand, when the finisher

23

is not connected to the image forming apparatus

500

, the ECONT

19

determines whether the detection result of the paper-full detecting sensor

823

, which detects whether a discharge tray for the discharged recording sheets is full, shows “full” (step S7). When the detection result of the paper-full detecting sensor

823

does not show “full”, the ECONT

19

performs other processing (step S8), while when the detection signal from the paper-full detecting sensor

823

shows “full”, the ECONT

19

sends back the status “full” to the IP

9

(step S9) and performs control so that printing is not performed on recording sheets (step S10).

Next, in

FIG. 11

, the ECONT

19

commences communication with the finisher

23

(step S11) and then determines whether the finisher

23

is in an abnormal state (step S12). When the finisher

23

is not in an abnormal state, the ECONT

19

performs the next process (step S16), while when the finisher

23

is in an abnormal state, the ECONT

19

sets the FOFF signal at off and resets the power supply of the finisher

23

(step S13), and determines once again whether the finisher

23

is in an abnormal state (step S14). When the finisher

23

is not in an abnormal state, the ECONT

19

performs the next process (step S17), while when the finisher

23

is in an abnormal state, the ECONT

19

sets the FOFF signal at off and turns off the power supply of the finisher

23

(step S15).

As described above, the CPU

102

of the controller (ECONT)

19

that controls the image forming unit of the image forming apparatus

500

transmits and receives information, such as status information and commands, to and from the CPU

103

of the finisher

23

via three-wire serial communication signals, and when an instruction for a switch to power saving mode is received from the CPU

101

of the controller (IP)

9

that controls the entire system comprised of the image forming apparatus

500

and the finisher

23

, the CPU

102

performs control to turn off the high voltage system of the image forming unit and turn off the power supply of the finisher

23

via the FOFF signal, thereby achieving the effects described below.

By providing an FOFF signal that can be reset together with the turning on and off of the control system power supply (5V) of the finisher

23

between the CPU

102

of the controller (ECONT)

19

, which controls the image forming unit of the image forming apparatus

500

, and the CPU

103

, which controls the various parts of the finisher

23

, the finisher

23

can be reset and its power supply turned off when the finisher

23

is in an abnormal state with a faster response than is possible with three-wire serial communication signals.

The on/off state of the power system power supply (24V), which is turned off during power saving mode on the image forming apparatus

500

side, is determined according to communication between the controller (ECONT)

19

and the controller (IP)

9

, and by controlling the timing in which the control system power supply of the finisher

23

is turned on and off by the controller (ECONT)

19

in accordance with the determined on/off state, erroneous operations of the finisher

23

can be prevented and a power saving mode can be achieved for the image forming apparatus

500

and the finisher

23

by appropriately turning off the power system power supply.

The controller (ECONT)

19

of the image forming apparatus

500

regards the three-wire serial communication input signal as an input port in predetermined timing, so that it can be detected whether the finisher

23

is connected to the image forming apparatus

500

at a low cost without adding a special signal to the interface.

When the controller (ECONT)

19

has detected that the finisher

23

is connected to the image forming apparatus

500

, the controller (ECONT)

19

informs the controller (IP)

9

that controls the entire system comprised of the image forming apparatus

500

and the finisher

23

of this fact, so that the finisher

23

can thereafter be controlled from the image forming apparatus

500

.

Also, in the case where there is an abnormality in the electric circuits or the like of the finisher

23

so that the finisher

23

that is physically connected to the image forming apparatus

500

does not operate electrically, and the controller (ECONT)

19

has judged that the finisher

23

is not connected to the image forming apparatus

500

, there is the possibility of a jam of recording sheets occurring when the recording sheets are discharged from the image forming apparatus

500

. However, a construction is used where the paper-full detecting sensor

823

is removed when the finisher

23

is attached to the image forming apparatus

500

. When the paper-full detecting sensor

823

has been removed, a discharge tray for the recording sheets is judged as being full in accordance with logic that is set in advance, so that control is performed not to discharge recording sheets from the image forming apparatus

500

to the finisher

23

, thereby making it possible to prevent recording sheet jams from occurring.

Other Embodiments

In the embodiment described above, as shown in

FIG. 5

the 5V voltage is applied to the SI signal via the resistor

919

. As shown in

FIGS. 12 and 13

, the voltage that is applied to the SI signal via the resistor

919

may be directly provided via the interfaces

901

and

1001

. By this construction, if the CPU

103

operates on a 5V power supply and the CPU

102

operates on a 3V power supply, for example, the high level of the SI signal can be set at 3V not 5V in keeping with the CPU

102

.

The above embodiment does not specify a particular kind of image forming apparatus, but the present invention may be applied to any kind of an image forming apparatus with an image forming function (i.e., a printer), an image forming apparatus with an image reading function and an image forming function (i.e., a copier), or an image forming apparatus with a plurality of functions such as an image reading function, an image forming function, and a facsimile function (i.e., a multi-function apparatus).

Although in the above embodiment, the image forming method employed by the image forming apparatus is an electro photocopying method, a variety of other image forming methods aside from the electro photocopying method, such as an ink jet method, a heat transfer method, and an electrostatic method, may be used.

Although in the above embodiment, a finisher, an inner discharge tray, and an option feeder are given as examples of options that can be detachably connected to the image forming apparatus, the present invention may be applied to options with functions aside from those of the options given above.

It should be noted that the present invention may either be applied to a system composed of a plurality of apparatuses or to a single apparatus. It is to be understood that the object of the present invention may also be accomplished by supplying a system or an apparatus with a storage medium or other medium in which a program code of software which realizes the functions of the above described embodiments is stored, and causing a computer (or CPU or MPU) of the system or apparatus to read out and execute the program code stored in the storage medium or other medium.

In this case, the program code itself read from the storage medium or other medium realizes the functions of the embodiments described above, and hence the storage medium or other medium on which the program code is stored constitutes the present invention. Examples of the storage medium or other medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, an optical disk, a magnetic-optical disk, a CD-ROM, a CD-R, a CD-RW, DVD-ROM, a DVD-RAM, a DVD-RW, a DVD+RW, a magnetic tape, a nonvolatile memory card, a ROM, or a download performed via a network.

Further, it is to be understood that the functions of the above described embodiments may be realized not necessarily by causing the computer to read and execute the program code, but also by causing an OS (operating system) or the like which operates on the computer to perform a part or all of the actual operations based on instructions of the program code.

Further, it is to be understood that the functions of the above described embodiments may be accomplished by writing a program code read out from the storage medium into an expansion board inserted into a computer or a memory provided in an expansion unit connected to the computer and then causing a CPU or the like provided in the expansion board or the expansion unit to perform a part or all of the actual operations based on instructions of the program code.

Number	Date	Country	Kind
2001-238262	Aug 2001	JP
2002-225998	Aug 2002	JP

Number	Date	Country
4-316880	Nov 1992	JP
2002-258691	Sep 2002	JP

Image forming apparatus and sheet processing apparatus with a serial connection

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (2)

Foreign Referenced Citations (2)