JP2003233226A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which accuracy in detecting the connection of an optional device is enhanced to suppress the occurrence of jamming, and also, a usability is made high. <P>SOLUTION: Since an SCLK signal, an SIN signal and an SOUT signal are common signals, the SIN signal as an input to a printer main body is outputted as an open collector output with reference to each optional device, so that the outputs may not collide with each other. An SEL 1 for specifying the optional device is connected to each optional device. As for a relation between the printer main body (a) and the optional device (b) in an optional communication control part, by disposing an R1 and an R2, the logic H when the optional device is connected is fixed to the logic L when the optional device is not connected, and by softly judging this level, whether or not the optional device is connected can be detected. <P>COPYRIGHT: (C)2003,JPO

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 for forming an image by an electrophotographic method, and more specifically, a connection detecting technique for an image forming apparatus and a feeding system optional apparatus added to the image forming apparatus. Regarding

[0002]

2. Description of the Related Art FIGS. 1 (a) and 1 (b) are schematic diagrams of an electrophotographic printer with and without a double-sided transport unit installed. FIG. 1 (a) shows an electrophotographic system with a double-sided transport unit not installed. FIG. 3 is a schematic configuration diagram of a printer. Reference numeral 101 in the drawing is
A photosensitive drum, which is an electrostatic carrier, a reference numeral 102 is a semiconductor laser as a light source, and a reference numeral 103 is a scanner motor 104.
Reference numeral 105 denotes a laser beam which is emitted from the semiconductor laser 102 and scans the photosensitive drum 101.

Reference numeral 106 is a charging roller for uniformly charging the photosensitive drum 101, and reference numeral 107 is a developing machine for developing the electrostatic latent image formed on the photosensitive drum 101 with toner. Is. Reference numeral 108 is a developing machine 107.
A transfer roller for transferring the toner image developed in 1 to a predetermined recording sheet, and a reference numeral 109 is a fixing roller for fusing the toner transferred to the recording sheet with heat.

Reference numeral 110 denotes a cassette paper feed roller which feeds paper from a cassette having a function of identifying the size of the recording paper by one rotation and sends it out to the transport path. Reference numerals 111 and 112 are transport rollers that transport the paper fed from the cassette.

Reference numeral 113 denotes a pre-feed sensor for detecting the leading edge and trailing edge of the sheet fed from the cassette.
Reference numeral 114 denotes a pre-transfer roller that feeds the conveyed paper to the photoconductor drum 101, and reference numeral 115 synchronizes image writing (recording / printing) to the photoconductor drum 101 with respect to the fed paper and paper conveyance. Together with this, it is a top sensor for measuring the length of the fed paper in the transport direction.

Reference numeral 116 is a paper discharge sensor for detecting the presence or absence of paper after fixing, reference numeral 117 is a paper discharge roller for discharging the paper after fixing to the outside of the machine, and reference numeral 120 is paper for the discharge unit. It is a full load detection sensor that detects the full load of. Reference numeral 118 is a main motor that drives the paper transport system and the periphery of the drum, and the transport rollers 111 and 112 are the clutches 1.
It is interlocked with the main motor 118 via 19.

R is a removable double-sided conveyance unit, which can be mounted in the direction of the arrow. Reference numeral 121 is a conveyance motor for rotating the conveyance rollers 117 of the main body forward and backward when the double-sided conveyance unit is mounted, and reference numeral 122 is a double-sided conveyance that always rotates in one direction to convey the recording paper in the double-sided conveyance unit. It's Laura. Reference numeral 123 is a re-feed motor that drives a re-feed roller for re-feeding the recording paper that has been reversed in the printer body, and reference numeral 124 is the leading and trailing ends of the recording paper in the re-feeding conveyance path. It is a sheet re-feeding sensor for detecting.

FIG. 1 (b) is a schematic configuration diagram after the double-sided conveyance unit is mounted. When the duplex unit is not connected, in FIG. 1A, the main roller drives the discharge roller 117 via the gear α. When the protrusion T displaces the gear α by mounting, the drive of the transport roller 117 is changed from the main motor 118 to the transport motor 12.
Forcibly switched to 1.

FIG. 2 is a block diagram illustrating a control configuration of the image forming apparatus shown in FIG. Reference numeral 201 in the figure is
The engine control unit (engine control unit) 202, which processes various control units, which will be described later, such as a printing operation based on a signal from the video controller,
The paper conveyance control unit executes paper conveyance / stop or timing control of ON / OFF of each roller based on the instruction 01.

Reference numeral 203 is a high voltage control section for controlling the timing and output value of each high voltage output for charging, development and transfer, and reference numeral 204 is an optical system control section for turning on / off the scanner motor and adjusting the laser light amount. Reference numeral 205 is a sensor input unit for transmitting the paper presence / absence information in each sensor to the engine control unit 201, and reference numeral 206 is a fixing unit temperature control unit for keeping the temperature of the fixing unit at a predetermined temperature by ON / OFF control.

Reference numeral 207 denotes an option communication control section for communicating with each feeding option of the duplex unit, envelope feeder and option cassette. Note that reference numeral 208
Is a double-sided conveyance control unit, reference numeral 209 is an envelope feeder control unit,
Reference numeral 210 indicates an option cassette controller.

As shown in FIG. 2, here, for each option (double-sided conveying unit, envelope feeder option cassette), / SEL1, / SEL2, respectively.
/ SEL3 is connected (in the following description, the symbol "/" means that the signal is low active). These signals / SEL1-3
Is a signal for specifying an option with which the option communication control unit 207 communicates, and each option can recognize that it is a communication target by logically making these signals “true”. .

Further, from the option communication control section 207, the / SCLK signal is connected to all options, and similarly, the / SIN signal and / SOUT signal are also connected as signals common to each option.

FIG. 3 is a circuit diagram of a communication control unit in a conventional example, and for simplicity, an input protection circuit and the like are omitted. Figure 3
2A and 2B, a printer main body CPU and an optional device (double-sided conveyance unit) CPU are shown. The other optional devices have the same configuration and will not be described.

As described with reference to FIG. 2, since the / SCLK signal, the / SIN signal, and the / SOUT signal are common signals, the / SIN signal, which is an input to the printer main body, is output as an open collector output with each optional device. , Outputs do not collide with each other. For other signals, the printer CPU and CP of optional equipment
The power supply Vcc 3.3V of U has the same voltage level, and therefore is directly connected through the resistor 100Ω.

In such a configuration, the option communication control section 207 sequentially exchanges commands and statuses for each option in time series.
Here, the command and status are, for example, a paper feed start command for instructing an optional device to start paper feed, a basic status request command for requesting an optional state, or the like. Usually the above command,
The optional connection is detected by exchanging the status.

[0017]

However, in the case of a structure in which the gear is forcibly switched when the option device is connected, such as the double-sided transport unit described in the prior art, and the drive is taken from the option device, the option is mounted and the drive is performed. Even if the device is switched to the optional device, there is a possibility that communication cannot be performed and the connection cannot be detected due to an electrical abnormality, for example, a runaway or destruction of the CPU. In such a case, the paper cannot be fed even during normal printing without using the optional device, which causes a jam, which is a problem.

The present invention has been made in view of the above problems, and an object thereof is to improve the accuracy of connection detection of an optional device, reduce the occurrence of jams, and improve the usability of the image forming device. To provide.

[0019]

In order to achieve such an object, the present invention provides an image forming apparatus for printing print data on a predetermined recording paper by an electrophotographic method. In, a plurality of drive or drive transmitting means for feeding the recording paper, an optional device of a feeding system having a detachable driving means, a communication means for controlling the optional device, and the communication means First connection detection means for detecting connection of the option device by performing a predetermined communication operation, and part of the drive or drive transmission means from the option device when the option device is mounted. A switching means for switching the electric signal level of the control signal in the communication means according to whether or not the optional device is connected, and the control signal. And having a second connection detecting means for detecting the connection of the electrical level option device.

The invention described in claim 2 is the same as claim 1.
In the invention described in (1), a measuring unit is provided as the electric level fixing unit, and the electric level of the control signal is fixed when a predetermined time has elapsed by the measuring unit.

The invention according to claim 3 is the same as claim 1
Alternatively, in the invention described in Item 2, the control signal is a selection signal unique to each of the plurality of option devices.

Further, according to a fourth aspect of the invention, in an image forming apparatus for printing print data on a predetermined recording paper by an electrophotographic method, a plurality of driving or drive transmitting means for feeding the recording paper are provided. A connection of the option device is detected by performing a predetermined communication operation by the communication device for controlling the option device of the feeding system having a detachable drive means, and the communication device. And a switching means for switching a part of the drive or drive transmission means to a driving means from the optional device when the optional device is mounted, and the driving of the switching device functions normally. And a second connection detecting means for detecting the connection of the optional device by the detecting means.

By adopting such a configuration, the CPU
Even if the option communication based on the command status cannot be performed due to destruction or runaway of the device, the connection of the option device can be detected by determining the electrical level of the communication control signal.

There is also a method of detecting a connection by separately providing a sensor like the option unit connection discriminating apparatus as disclosed in Japanese Patent Laid-Open No. 8-332755, but in the present invention, the communication unit which has been conventionally used is used. Utilizing the control signal and the sensor is advantageous in terms of space and cost.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 4 is a control block diagram of an electrophotographic printer which is an image forming apparatus according to the present embodiment, and FIG. 5 is a circuit diagram of an option communication controller in the first embodiment. Then, FIG. 7 is a diagram showing a flowchart for explaining the process of the option connection detection unit.
Note that, in FIG. 4, portions having the same configuration shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted here. Reference numeral 401 is an option connection detection unit for detecting an option connection.

In FIG. 5, a is a printer main body CPU,
b is an optional device CPU. Here, V1 = Vcc1 * R1 / (R1 + R2) ... (1) V2 = V1-R3 * Ibih ... (2) is established.

By providing R1 and R2, the logic when the option device is not connected is fixed to the logic L when it is connected, and the presence or absence of the connection of the option device is detected by judging this level by software. Will be possible. Here, R1, R2, and R3 are set so that V2> the H-level detection threshold value of the CPU from the above equations (1) and (2).

The processing of the option connection detector will be described below with reference to the flowchart shown in FIG. The option connection detection unit 401 is activated when the power is turned on or when an abnormality occurs in the communication due to the command status (S700). In step S701, the port I / O1 which is an input / output port is set as an input port. S702
If the input level is detected at and the input level is GND, the option device (here, the double-sided unit) is not connected at S706 (S707), and the port I / O1 is monitored at any time.

If the input level is H in S702, the process proceeds to S703. Here, if a communication error occurs in S700, it is determined that the option device has failed.
If no communication error has occurred, the port I / O is set to the output port, and communication control by the command / status is started in S704.

[Second Embodiment] FIG. 6 is a circuit diagram of an option communication control section of an electrophotographic printer which is an image forming apparatus according to this embodiment. a is the printer body CP
U and b are optional device CPUs. WT is a watchdog timer which is a measuring means and outputs an L level when the input I does not change for a predetermined time T or longer. FIG. 9 shows a time chart of the watchdog timer WT.

The / SEL1 signal is fixed at H level while the input I of the watchdog timer WT is accessed at predetermined intervals by the optional device, and the / SEL1 signal is fixed at L level unless the optional device is connected and the access is not made. It By judging this level by software, it is possible to detect whether or not the optional device is connected. This connection detection method has been described with reference to FIG.

[Third Embodiment] FIG. 10 is a schematic block diagram of an electrophotographic printer which is an image forming apparatus according to this embodiment, and FIG. 11 illustrates processing of an option connection detection unit according to this embodiment. It is a figure which shows the flowchart for. The same components as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted here. In the figure, reference numeral f is a flag that interlocks with the paper discharge roller 117 and sets the full load detection sensor 120 to the presence or absence of paper. FIG. 9 is a time chart showing the relationship between the motor for driving the paper discharge roller and the full load detection sensor.

A is driving the motor. When the motor is turned on, the flag f moves up and down in conjunction with it, so the full load detection sensor 120 outputs a pulse waveform. b indicates during the printing period. During printing, while the paper is being ejected, the full-load detection sensor 120 outputs the pulse waveform between the papers and when the motor is ON during the paper interval. The period c represents a full load, and the full load detection sensor 120 always outputs the presence of paper.

The processing of the option connection detector will be described below with reference to the flowchart shown in FIG.
The option connection detection unit 401 is activated when the motor is turned on (S1100). When activated, the timer T is reset and the timer starts counting (S1101). S11
If there is paper in the full load detection sensor 120 in 02, S110
If there is no paper, it is determined whether the timer T is equal to or longer than a preset t1.

If t1 or less, go to S1102.
If t1 or more, it is considered that the discharge roller 117 is not normally driven, and the process proceeds to S1110. If the communication by the command status is normally performed in S1110, the motor is abnormal (S1111). If the communication is not abnormal or communication is not performed here, it is determined that the connection of the option is abnormal (S1112).

In step S1103, the timer T is reset again and timer counting is started. If the full load detection sensor 120 is out of paper in S1104, it is determined in S1105. If not, it is determined in S1106 whether the timer T is equal to or longer than the preset t2. If t2 or less, S110
If t2 or more, it is detected that the paper discharge section is full. If the motor is detected to be OFF in S1105, the process ends.
If it is not turned off, the process proceeds to S1101 and the same process is repeated.

[0038]

As described above, according to the present invention, C
Even if the option communication based on the command status cannot be performed due to the destruction or runaway of the PU, the connection of the option device can be detected by determining the electrical level of the communication control signal.

Further, it is possible to detect the connection of the optional device by having a detecting means for detecting whether the switching section is normally driven.

Therefore, even when the optional device is forced to switch gears and drive when the optional device is connected, it is possible to accurately detect an abnormality in the optional device and provide an image forming apparatus with high usability. become.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic printer with or without a double-sided transport unit attached, in which (a) is a diagram before a double-sided transport unit is mounted and (b) is a diagram after a double-sided transport unit is mounted.

FIG. 2 is a control block diagram of an electrophotographic printer in a conventional example.

FIG. 3 is a circuit diagram of a communication control unit in a conventional example.

FIG. 4 is a control block diagram of the electrophotographic printer according to the embodiment of the present invention.

FIG. 5 is a circuit diagram of an option communication controller in the first embodiment of the present invention.

FIG. 6 is a circuit diagram of an option communication controller according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a flowchart of an option connection detection unit in the embodiment of the present invention.

FIG. 8 is a diagram showing a time chart of a watchdog timer according to the second embodiment of the present invention.

FIG. 9 is a diagram showing a time chart of the full load detection sensor in the third embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of an electrophotographic printer according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a flowchart of an option connection detection unit in the third exemplary embodiment of the present invention.

[Explanation of symbols]

101 photoconductor drum 102 Semiconductor laser 103 rotating polygon mirror 104 scanner motor 105 laser beam 106 charging roller 107 developing machine 108 transfer roller 109 fixing roller 110 paper feed roller 111,112 Transport rollers 113 Pre-feed sensor 114 pre-transfer roller 115 Top sensor 116 Paper ejection sensor 117 Paper ejection roller 118 Main motor 119 clutch 120 full load detection sensor 121 Conveyor motor 122 double-sided conveyance roller 123 Refeed motor 124 Refeed sensor R Double-sided transport unit 201 Engine control unit (engine control unit) 202 Paper transport control unit 203 High voltage controller 204 Optical system controller 205 sensor input section 206 Fixer temperature controller 207 Optional communication controller 208 double-sided conveyance control unit 209 Envelope feeder control unit 210 Optional cassette controller 401 Optional connection detector

Claims (4)

[Claims] 1. An image forming apparatus for printing print data on a predetermined recording paper by an electrophotographic method, comprising a plurality of driving or drive transmitting means for feeding the recording paper, and a detachable driving means. An optional device of a transmission system, a communication device for controlling the optional device, and a first connection detecting device for detecting a connection of the optional device by performing a predetermined communication operation by the communication device, And a switching means for switching a part of the drive or drive transmission means to the drive means from the optional device when the optional device is mounted, and the electrical level of the control signal in the communication means depending on whether the optional device is connected or not. And a second connection detecting means for detecting the connection of the optional device according to the electrical level of the control signal. Image forming apparatus characterized by. 2. The measuring means is provided as the electric level fixing means, and the electric level of the control signal is fixed when a predetermined time elapses by the measuring means. The image forming apparatus according to item 1. 3. The image forming apparatus according to claim 1, wherein the control signal is a selection signal unique to each of the plurality of option devices. 4. An image forming apparatus for printing print data on a predetermined recording sheet by an electrophotographic method, comprising a plurality of driving or drive transmitting means for feeding the recording sheet, and a detachable driving means. An optional device of a transmission system, a communication device for controlling the optional device, and a first connection detecting device for detecting a connection of the optional device by performing a predetermined communication operation by the communication device, Switching means for switching a part of the drive or drive transmission means to drive means from the optional device when the optional device is mounted, and detecting means for detecting that the drive of the switching means is functioning normally. An image forming apparatus comprising: a second connection detecting unit that detects the connection of the optional device by the detecting unit.