JPS63316875A - Controller for image forming device - Google Patents

Abstract

PURPOSE:To eliminate malfunction by resetting an output mode periodically while data is outputted through a port which is set in the output mode. CONSTITUTION:Input/output ports 35 and 42 are used as input or output ports according to the setting of port mode data to a port usage setting register by a microcomputer 31. A ROM 43 is stored with a subroutine which redefines the usage of a port when data is inputted through the port set as an input port in addition to a main program and an initial setting program for copying operation, and the contents of the usage setting register of the port 35 are reset to the input mode right before the input data is read in the computer 31 through the port 35. Even if the contents of the usage setting register are destroyed before the input port input subroutine is executed, the input data from the port 35 is invariably set for the input port and then inputted. Thus, wrong data is prevented from being inputted to the computer 31.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to an image forming apparatus that is equipped with a microcomputer and peripheral elements having built-in input/output ports, and controls an electronic copying machine, etc. The present invention relates to a control device for a device.

(Prior Art) As is well known, electronic copying machines are equipped with microcomputers and the like to provide multifunctionality and improve copying performance.

By the way, micro-combiners have, for example, input/output ports (which can be both input ports and output ports), and depending on whether the same port is used for input or output, Some devices have a built-in port usage setting register for storing the operating mode.

Conventionally, the data in the above port usage setting register (port mode data that sets whether the port is for input or output) is stored after the power of the microcomputer is turned on or immediately after the microcontroller is turned on. It is written when the initial setting program is executed, such as after a reset signal is input. However, if the contents of the port usage setting register (port mode data) are destroyed due to static electricity shock or power line noise after the copier is put into operation, or if the output data is destroyed, - There was a problem in that the computer would output incorrect data, causing the copying machine to malfunction.

(Problems to be Solved by the Invention) This invention solves the problem when the contents of the port usage setting register are destroyed due to static electricity shock or power line noise after the copying machine is put into operation, or when the output data is This eliminates the problem that if the port is destroyed, the microcomputer will output incorrect data, causing the copier to malfunction. Destruction of the port mode data that sets the port's operating mode Another object of the present invention is to provide a control device for an image forming apparatus that can prevent malfunctions due to destruction of output data.

[Configuration of the Invention (Means for Solving Problems) The control device for an image forming apparatus according to the present invention includes a setting means for setting an operation mode of a port, and an output mode set by the setting means. The control means periodically resets the port to output mode while data is being output via the port.

(Operation) According to the present invention, while data is being output from a port, the port is periodically reset to the output mode.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 3 schematically shows an image forming apparatus of the present invention, such as a copying machine. That is, a document table (transparent glass) 2 that supports a document is fixed to the top surface of the copying machine main body 1 . The document table 2 is provided with a fixed scale 21 that serves as a reference for setting the document, and furthermore, a document cover 11 and a work table 12, which can be opened and closed, are provided near the document table 2.

The original placed on the original table 2 is exposed and scanned by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 being reciprocated in the direction of arrow a along the lower surface of the original table 2. It is now possible to do so.

In this case, mirror 6.7 is moved at half the speed of mirror 5 so as to maintain the optical path length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4, is reflected by the mirror 5, 6, 7, passes through the variable magnification lens block 8, and is further reflected by the mirror. 9 and guided to the photoreceptor drum 10, an image of the document is formed on the surface of the photoreceptor drum 10.

The photosensitive drum 10 is rotated in the direction of arrow C in the figure, and the surface thereof is first charged by the charging device 11 . Thereafter, the image is subjected to slit exposure in the exposure section, thereby forming an electrostatic latent image on the surface. This electrostatic latent image is made visible by applying toner by the developing device 12.

On the other hand, the paper (transfer material) P is taken out one by one from the selected upper paper feed cassette 13 or lower paper feed cassette 14 by the delivery roller 15 or 16, and the taken out paper is taken out from the paper guide path 17 or 18, and is guided to a pair of registration rollers 19, and is fed to a transfer section by this pair of registration rollers 19. Here, the paper feed force rollers 13 and 14 are removably provided at the lower right end of the main body 1, and one of them can be selected from an operation panel (not shown). Note that the paper size inside each of the paper feed cassettes 13 and 14 is recognized from the cassette size detected by a cassette size detection switch 601 and 602, respectively. The cassette size detection switches 60□, 602 are composed of a plurality of microswitches that are turned on and off depending on the insertion of cassettes of different sizes, for example.

The paper P sent to the transfer section is brought into close contact with the surface of the photoreceptor drum 10 at the transfer charger 20, and
The toner image on the photoreceptor drum 10 is transferred by the action of 0. The transferred paper P is electrostatically peeled off from the photoreceptor drum 10 by the action of a peeling charger 21, and is sent by a conveyor belt 22 to a pair of fixing rollers 23 as a fixing device provided at the end of the conveyor belt 22. . The transferred image is fixed by passing through this, and the fixed paper P is discharged to a tray 25 outside the main body 1 by a pair of paper discharge rollers 24.

Further, the photoreceptor drum 10 after the transfer is transferred to a charger 26 for removing static electricity.
After the charge is removed by the cleaner 27, residual toner on the surface is removed, and the afterimage is erased by the charge removal lamp 28, so that the initial state is restored. Note that 29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

FIG. 4 shows an outline of the control circuit. That is,
The microcomputer 31 includes a copy key provided on an operation panel (not shown) for commanding the start of copying, an input key 32 such as a numeric keypad for setting the number of copies, etc., a sensor 33 for detecting the temperature of a heater (described later), and the cassette. Various switches 34 such as size detection switches ao, ao2 and a switch for detecting passage of paper P (not shown)
data (input data) is inputted through the input/output port 35, and the charger transformer 36 drives the various chargers, the heater 23a1 of the fixing roller pair 23, the exposure lamp 4
, a paper feed motor 37 that drives the delivery rollers 15 and 16;
A scanning motor 38 that moves the exposure lamp 4 and mirrors 5, 6, 7 for document scanning, a developing motor 39 that drives the developing roller of the developing device 12, and the photosensitive drum 10.
Displays the operating status of the drum motor 40 that drives the copying machine, the state of paper jam, etc., displays the selection of the upper or lower paper feed cassette 13 or 14, and displays the copy enlargement or reduction magnification.

The above-described copying operation is performed by outputting data (output data) via an input/output port 42 such as a display 41 that displays the copy density, the set number of copies, etc. ing.

The input/output ports 35 and 42 function as input or output ports, and can be used as input ports or output ports depending on the setting of port mode data in a port usage setting register (not shown) by the microcomputer 31. It is now in use. In addition, the fourth
In the illustrated embodiment, input/output port 35 is used as an input port and input/output port 42 is used as an output port.

The microcomputer 31 also includes a ROM (read/write memory) in which control programs and the like are stored, for example.
RA (only memory) 43, which stores input data input via the input/output port 35 or output data output via the input/output port 42
M (random access memory) 44. The ROM 43 stores, for example, an input port input subroutine and an output port output subroutine in addition to a main program and an initial setting program for performing basic copying operations.

FIG. 2 shows the input port input subroutine. This program redefines that when inputting data via an input/output port set as an input port, the input/output port is used again as an input port. 3
5, the contents of the port usage setting register of the input/output port 35 are reset to the input mode immediately before reading the input data via the input/output port 5.

That is, in step STI, the input/output port 35 used as an input port is reset as an input port again. In this case, data (port mode conflict data) for enabling the input/output port 35 to be used as an input port is written in the port usage setting register.

In step ST2, various signal data (input data) are read by the microcomputer 31 via the input/output port 35 set as an input port. Here, by programming to minimize the time gap between steps ST1 and ST2, if the contents of the port usage setting register are destroyed by static electricity etc. before the input port input subroutine is executed. Even if such a situation occurs, data input via the input/output port 35 is always input after being set as an input port. Therefore, it is possible to prevent incorrect data from being input into the microcomputer 31.

In step ST3, the input data is stored in the RAM 44. In this way, when inputting data via the input/output port 35, it is always done via the input port input subroutine.

FIG. 1 shows the output port output subroutine of the present invention. While this program is outputting data via the input/output port set as an output port,
This redefines the use of the input/output port as an output port, and while the microcomputer 31 is outputting output data via the input/output port 42, the port usage of the input/output port 42 is periodically The contents of the setting register are reset to output mode.

That is, in step 5T11, the output data is stored in the RAM.
In the state stored in 44, the input/output port 42 used as an output port is set as an output port again. In this case, data (port mode φ data) for enabling the input/output port 42 to be used as an output port is written in the port usage setting register.

In step 5T12, the data stored in the RAM 44 is output to each section via the input/output port 42 set as an output port. Here, step 5TI
By programming so that the time gap between I and 5T12 is as small as possible, and by ensuring that this subroutine is executed at regular intervals, if the output port output subroutine finishes execution and is executed again. Even if the contents of the port usage setting register or the data being output are destroyed by static electricity etc. until incorrect data is output via the input/output port 42, the input/output Data output from port 42 is immediately restored by the contents of RAM 44. Therefore, the time during which erroneous data is output from the port 42 can be minimized.

Next, the operation of the above configuration will be explained. For example, now
Assume that the microcomputer 31 is powered on by turning on a power switch (not shown) of the copying machine main body 1. Then, by writing port mode data into the port usage setting register by the microcomputer 31, the input/output port 35 is set as an input port, and the input/output port 42 is set as an output port.

First, data to be output to the heater 23a, for example drive command data that instructs the heater 23a to heat, is stored in the RAM 44. Thereafter, the data stored in the RAM 44 is output to the heater 23a. In this case, data is output to the heater 23a via the input/output port 42 according to the output port output subroutine shown in FIG. That is, the input/output port 42 used as an output port is reset as an output port,
The data stored in the RAM 44 is output to the heater 23a via the input/output port 42 that has been reset as an output port. Thereafter, data is similarly output according to the output port output subroutine.

As a result of this step 5, when the heater 23a is heated to reach the fixing temperature, data detected by the sensor 33 is input to the microcomputer 31. In this case, data input from the sensor 33 is performed via the input/output port 35 according to the input port input subroutine shown in FIG. In other words, the input/output port 35 used as an input port is reset as an input port, and the input port □
Sensor 3 via input/output port 35, which has been reconfigured as
3 is input to the micro φ computer 31. Thereafter, data is similarly input according to the input port input subroutine.

Then, based on the data from the sensor 33, the RAM
Stop command data for stopping heating of the heater 23a is stored in 44. Thereafter, the data stored in the RAM 44 is output to the heater 23a via the input/output port 42 according to the output port output subroutine. and,
When stop command data is output to the heater 23a, heating of the heater 23a is stopped and the fixing temperature is maintained.

As a result, the copying machine main body 1 is enabled for operation, and the data for lighting the ready lamp (not shown) is stored in the RAM 4.
It is stored in 4. This data is then output to the display 41 via the human output port 42 according to the output port output subroutine, thereby lighting up the ready lamp on the display 41.

In this state, when copying conditions such as the number of copies and image density are entered from the operator panel 32 (not shown), these data are sent via the input/output port 35 according to the input port 1 input subroutine. The data is then input to the micro or computer 31. Then, the data displaying each copying condition described above is stored in the RAM 44 and output to the display 41 via the input/output port 42 according to the output port output subroutine. As a result, the display 41
Accordingly, selection display of the upper or lower paper feed cassette 13 or 14, display of copy enlargement or reduction magnification, display of copy density, display of set number of copies, etc. are performed.

Thereafter, when a copy start instruction is inputted from the input key 32 in response to the operation of a copy key (not shown) on the operation panel, this copy start instruction data is sent to the input/output port 35 according to the input port input subroutine. The signal is inputted to the microcomputer 31 via the computer. Then, instruction data to turn off the ready lamp is stored in the RAM 44, and this data is output to the display 41 via the input/output port 42 according to the output port output subroutine, thereby turning off the ready lamp. Ru.

Next, drive signal data for controlling the developing motor 39 that drives the developing device 12, drive signal data for controlling the paper feeding motor 37 that drives the feed rollers 15 and 16, and a drum motor that drives the photosensitive drum 10. 40, drive signal data to control the exposure lamp 4, and charger transformer 36 to drive various chargers.
Drive signal data for controlling the is sequentially stored in the RAM 44, and each of these data is sequentially transmitted to the developing motor 39, the paper feeding motor 37, the drum motor 40, via the input/output port 42 according to the output port output subroutine. By outputting to the exposure lamp 4 and charger transformer 36, the developing device 12, the delivery roller 15, 16, the photosensitive drum 10, the exposure lamp 4, and the various chargers 11
°20.21 etc. are driven.

Further, drive signal data for controlling the scanning motor 38 is stored in the RAM 44, and this data is outputted to the scanning motor 3B via the input/output port 42 according to the output port output subroutine, so that the exposure lamp 4. The movement of the mirror 5°6.7 is started and the reading of the original image is performed.

When the switch 34 detects that the ejection of the paper P from the photosensitive drum 10 on which the toner image has been formed is completed by the operation of the delivery rollers 15 and 16 driven by the paper feed motor 37, this switch The data from 34 is sent to the microcomputer 31 via the input/output port 35 according to the input port input subroutine.
is input. Then, instruction data for stopping the drive of the paper feed motor 37 is stored in the RAM 44, and this data is output to the paper feed motor 37 via the input/output port 42 according to the output port output subroutine. As a result, the drive of the delivery rollers 15 and 16 is stopped.

Further, when the switch 34 detects that the exposure lamp 4 and the mirror 5, 6, 7 have returned to their initial positions, the data from the switch 34 is transferred to the microcontroller via the input/output port 35 according to the input port input subroutine. - Input to computer 31. Then, instruction data to stop driving the scanning motor 38, instruction data to turn off the exposure lamp 4, and instruction data to turn off various chargers are sequentially stored in the RAM 44, and each of these data is outputted according to the output port output subroutine. , are sequentially output to the scanning motor 38, the exposure lamp 4, and the charger transformer 36 via the input/output port 42, thereby stopping the movement of the exposure lamp 4, mirrors 5, 6°7, and the exposure lamp 4. is turned off, and the driving of various chargers 11, 20, 21, etc. is stopped.

After that, when the switch 34 detects that the transfer of the toner image to the paper P is completed, the switch 34
Data is input to the microcomputer 31 via the input/output port 35 according to the input port input subroutine.

Then, the instruction data for stopping the driving of the developing motor 39 and the instruction data for stopping the driving of the drum motor 40 are sequentially stored in the RAM 44, and these data are sequentially sent to the input/output port 42 according to the output port output subroutine. Via the developing motor 39 and drum motor 4
By outputting the signal to 0, the driving of the developing device 12 and the photosensitive drum 10 are respectively stopped.

Then, when the switch 34 detects that the paper P on which the transferred image is fixed is discharged onto the tray 25,
Data from this switch 34 is input to the microcomputer 31 via the input/output port 35 according to the input port input subroutine. Then, instruction data for lighting the ready lamp is stored in the RAM 44, and this data is output to the display 41' via the input/output port 42 according to the output port output subroutine, thereby indicating that the display 41 is ready. A lamp is displayed. With the above, the series of copying operations described above is completed.

As described above, the contents of the port usage setting register that defines whether an input/output port is used as an input port or an output port is reset (refreshed).

That is, while data is being output via an input/output port, that port is periodically reset to output mode. This makes it possible to minimize the time during which erroneous data is output from the input/output port. Therefore, even if the contents of the port usage setting register or output data are destroyed due to static electricity shock or power line noise, the copier that is the object of control will be prevented from malfunctioning. This makes it possible.

Further, the present invention can be easily implemented by adding a program without changing the hardware configuration of the copying machine.

In the above embodiments, a copying machine is used as an example of an image forming apparatus, but the present invention is not limited to this, and can be applied to printers, facsimile machines, and the like.

Further, although the input/output port externally attached to a microcomputer has been described, the present invention can also be applied to, for example, a port built into a microcomputer or a port built into a peripheral element.

Further, the operation mode (input mode/output mode) may be set on a circuit-by-circuit basis or on a terminal-by-terminal basis.

In addition, although general-purpose input/output ports are used as output ports, parallel type/output interface LSI
(Large Scale Integration
n), for example, PPI (programmable φ peripheral interface: NEC μPD8255, etc.)
may be used as an output port. This PPI includes:
Some devices have built-in port usage setting registers and storage means such as RAM, and the port usage (input mode/output mode) can be set by writing port mode data to the above registers. There is.

However, in the case of this type of PPI, when port mode data is written to the register, a state occurs in which all the output ports are at a low logic level within a certain period of time.

Therefore, when the output mode is set periodically, a low level signal is output from the output port each time.

Therefore, when using the PPI as described above as an output port, control by the output port output subroutine shown in FIG. 5, for example, becomes effective.

In this case, only when the data being output from the PPI output port and the data from the microcomputer do not match, it is determined that the contents of the port usage setting register or output data have been destroyed, and the output mode to the register is changed. The settings are reset and the output data is re-outputted to the storage means. Note that this output port output subroutine can also be applied to setting the operating mode of a port usage setting register built in a microcomputer or its peripheral elements.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, there is provided an image forming apparatus that can prevent malfunctions due to destruction of port mode data for setting the operation mode of a port or destruction of output data. control device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of an output port output subroutine explaining the operation of a control device of an image forming apparatus showing an embodiment of the present invention, FIG. 2 is a flowchart of an input port input subroutine, and FIG. 3 is a flowchart to which the present invention is applied. 4 is a block diagram schematically showing the control circuit of the copying machine, and FIG. 5 is a side sectional view showing the configuration of an electronic copying machine according to the present invention. It is a flowchart. 1... Copying machine main body, 4... Exposure lamp, 10...
Photosensitive drum, 11... Charger, 12... Developing device, 15.16... Delivery roller, 23a... Heater, 31... Micro computer, 32... Input key. 133...Sensor, 34...Switch, 35
...Input/output port (input port), 36...Charger transformer, 37...Paper feed motor, 38...Scanning motor, 39...Developing motor, 40...Drum use Motor, 41... Display unit, 42... Input/output port (output port). Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] Setting means for setting the operation mode of a port, and periodically setting the port to the output mode while data is being output via the port set to the output mode by the setting means. What is claimed is: 1. A control device for an image forming apparatus, comprising: control means for resetting settings.