JPH03259325A - Data transmission system - Google Patents

Abstract

PURPOSE:To transmit data at high speed by receiving the data from a first device with a second device, performing the processing of the data, outputting a permission signal to the first device when completing the processing, and outputting the data in accordance with the reception permission of the second device from the first device to the second device. CONSTITUTION:Reception data (a) from a host device 409 is supplied to and stored in a page buffer 403a. After that, a CPU 401 checks whether or not a null buffer 403a exists, and when it is filled, a set signal (d) is sent from an input/output port 408a to an FF 408b. Thereby, set output is inverted at an inverter circuit 408c, and a busy signal is outputted to the device 409. The degree of vacancy of the buffer 403a is checked i.e. whether or not it approaches near-end. When no near-end state is detected, the CPU 401 continues the delivery of a reset signal (e) from the port 408a to the FF 408b. In such a way, the FF 408b remains reset, and the busy signal from the circuit 408c remains turned off, then, the data can be sent from the device 409 at the highest speed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus, for example, between a host device and an image forming device such as a laser printer that performs print processing according to data from the host device. The present invention relates to a data transmission system for transmitting data.

(Prior Art) Conventionally, when transmitting data between a personal computer as a host device and a peripheral device such as a printer, a parallel interface has been used to perform high-speed data transmission.

In a typical parallel interface, a printer serving as a receiving device sends a mid-busy signal to inform the host device whether or not it is capable of receiving data. The host device checks the busy signal and sends the data if it is off. When the printer receives data, it turns on the busy signal until it is ready to receive the next data.

As a result, data is sent byte by byte from the host device to the printer side according to the above transmission procedure.

Therefore, each time the host device sends out one byte of data, it checks the status of the printer side for the busy signal, confirms that the printer side is ready for reception, and then sends the next data. This busy signal confirmation is normally performed at regular intervals, so the printer can receive it during the host device's confirmation, and even if the busy signal is turned off, data transmission will be stopped until the next confirmation. This has the disadvantage that high-speed data transmission is not possible.

(Problem to be Solved by the Invention) As described above, this invention eliminates the disadvantage that data transmission cannot be performed at high speed when transmitting data from a first device to a second device. An object of the present invention is to provide a data transmission system that can perform data transmission at high speed when transmitting data from one device to a second device.

[Structure of the Invention] (Means for Resolving the Problem) The data transmission system of the present invention transmits data from a first device to a second device, and the data transmission system transmits data from a first device to a second device. a receiving means for receiving data from the apparatus; a processing means for performing processing according to the data received by the receiving means; a determining means for determining whether the processing by the processing means has ended; reception permission output means for outputting a reception permission to the first device in response to the reception permission from the second device; It is equipped with an output means.

(Operation) The present invention transmits data from a first device to a second device, in which the second device receives data from the first device and responds to the received data. When it is determined that the process is finished, a reception permission is output to the first device, and the first device transfers the data to the second device in accordance with the reception permission from the second device. It is designed to output to the following device.

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

FIG. 2 shows the configuration of an image forming unit connected to the data transmission system of the present invention, such as an image forming unit device including a laser printer and optional equipment. That is, the image forming unit device uses paper (plain paper) P of a predetermined thickness such as cut paper as an image forming medium.
A multi-cassette feeder 2 that feeds paper into the laser printer 1, an envelope feeder 3 that feeds paper (cardboard) A that is thicker than plain paper such as 1/J cylinders as a transfer material into the laser printer 1, An optional device such as a jogger (not shown) is connected to the laser printer 1 to perform sorting of the sheets P or envelopes A into predetermined numbers. The printing rate on the envelope A is low (the amount of toner used as a developer is small). The multi-cassette feeder 2, envelope feeder 3, and jogger are connected online to a control section (not shown) in the main body of the laser printer 1.

An operation panel (not shown) is provided on the upper surface of the laser printer 1.

Further, inside the laser printer 1, a laser optical system 12, a photosensitive drum 17, a charging device 18, a developing device 19, a transfer device 20, a static eliminator 21, a peeling device 35, a fixing device 37,
In addition to process systems such as a cleaning device 45, a paper feed cassette 22, a delivery roller 23, and an aligning roller pair 25
, conveyor belt 36, gate 38, paper ejection roller pair 39.4
2 etc. are provided. The laser optical system 12 includes a semiconductor laser oscillator (not shown) that generates laser light;
A collimator lens (not shown) corrects the laser beam from this oscillator into parallel light, a polygon mirror (rotating mirror) 13
, f/θ lens 14, mirrors 15, 16, and a mirror motor 60 that rotates (drives) the polygon mirror 13.
It is composed of etc.

During the image forming operation, a laser beam from the laser optical system 12 corresponding to an image signal from an external device (not shown) or an operation panel (not shown) forms an image on the surface of the photosensitive drum 17.

The photosensitive drum 17 rotates in the direction of the arrow shown in the figure, and the surface thereof is first charged by the charging device 18, and then exposed by the laser optical system 12 in accordance with an image signal. That is, the laser beam generated from the semiconductor laser oscillator is scanned at a constant speed from the left to the right of the photosensitive drum 17 as the polygon mirror 13 is rotated by the mirror motor 60, thereby creating an electrostatic charge on the surface of the photosensitive drum 17. A latent image is formed. This electrostatic latent image is processed by the developing device 19 using toner (
The image is visualized by adhering developer) t.

On the other hand, the paper P serving as the image forming medium from the paper feed cassette 22 is taken out one by one by the delivery roller 23, and
4, and is guided to a pair of aligning rollers 25, and sent to a transfer section by this pair of rollers 25.

Also, to the transfer section, the paper P or the paper feed that is taken out one by one by the feed roller 32 from the paper feed cassette 30 in the multi-cassette feeder 2 and guided to the aligning roller pair 25 through the paper guide path 34.29. paper cassette 3
The paper P1 is taken out one by one by the delivery roller 33 from 1 and guided to the pair of aligning rollers 25 through the paper guide path 34.29, or the paper P1 is taken out one by one from the stacker 26 in the envelope feeder 3 by the delivery roller 27. The aligning roller pair 2 passes through the paper guide path 28 and 29.
The envelope A guided to the aligning roller pair 25 and the paper P fed from the manual paper feed section 44 and guided to the aligning roller pair 25 through the paper guide path 29 are fed from the external device or the operation panel (not shown). It will be sent according to your specifications.

Then, the paper P or envelope A sent to the transfer section is brought into close contact with the surface of the photoreceptor drum i7 at the transfer device 20, and the toner image on the photoreceptor drum 17 is transferred by the action of the transfer device 20. . The transferred paper P or envelope A is peeled off from the photosensitive drum 17 by the action of the peeling device 35, and is sent to the fixing device 37 by the conveyor belt 3B, where it passes through a heat roller that generates heat for fixing. 371, the transferred image is thermally fixed. This heat roller 37. A heater lamp 37a for heating is built inside. After fixing, the paper P or envelope A passes through a gate 38 and is delivered to the paper ejection tray 4 by a pair of paper ejection rollers 39.
0 or the upper conveying path 4 by the gate 38
1, and is sent to the paper ejection tray 43 by the paper ejection roller pair 42.
It is designed to be discharged upward.

Further, the photosensitive drum 17 after the transfer is cleaned by a cleaning device 4.
After the residual toner is removed in step 5, the residual image is erased by the static eliminator 21, so that the next image forming operation is
=J is considered to be in a capable state.

The fixing device 37 is formed into a unit (fuser unit), and is configured to be able to be attached to and detached from the laser printer 1 independently. Further, in front of the pair of aligning rollers 25, there is an aligning switch 48 for detecting a paper feeding error to the transfer section by the pair of aligning rollers 25, etc.; , paper ejection switches 49a and 49b are provided for detecting paper ejection errors by the paper ejection roller pairs 39 and 42, respectively.

In addition, the paper feed cassette 22, 30, 31 has paper P
Paper detectors 50, 51, and 52 are arranged to detect the presence or absence of paper P in the paper feed cassettes 22, 30, and 31, respectively.

Further, above the laser optical system (2), there is an engine control board equipped with an engine control circuit 70 that controls each electrical device provided in the apparatus main body l to control operations to complete the electrophotographic process, and A board on which a printer control circuit 71 for controlling the operation of the engine control channel 70 is mounted is disposed.

Up to three boards for the printer control circuit 71 can be installed depending on the degree of function addition (for example, adding more types of fonts, kanji, etc.). Further functions can be added by inserting a function-adding IC card 517 into three IC card connectors 72 arranged on the front edge of the board 71. Furthermore, a connector (not shown) for connecting to a host device 409 (described later), which is an external output device such as a computer or word processor, is provided on the left end surface of the board of the printer control circuit 71 located at the bottom. There is.

Next, the configuration of the engine control section will be explained.

FIG. 3 is a block diagram showing the configuration of main parts of the engine control section 300. In the figure, 302 is a power supply device;
By turning on the main switch 301, power supply voltages of +5V and +24V are output. The power supply voltage of +5V is supplied to the engine control circuit 70, and is further supplied to the printer control circuit 7 via this engine control circuit 70.
1.

On the other hand, for +24V power supply voltage, use cover switch 303.30
4 is sequentially supplied to the engine control circuit 70. The power is then supplied to the scanner control circuit 101, the high voltage power supply 305, and the mechanism drive circuit 306 through the engine control circuit 70, respectively. A semiconductor laser 90 and a mirror motor 9 are connected to the scanner control circuit 101.
2, the main motor 307 of the pre-exposure device 2L, the manual paper feed solenoid 308, the cassette paper feed solenoid 309, and the aligning solenoid 31 from the mechanism drive circuit 30B.
0, toner supply solenoid 311, and cooling fan 5
00, etc., and used as a driving power source for these. When the paper feed solenoid 309a is turned on, the feed roller 23 rotates once, and the paper P is taken out from the paper feed cassette 22.

Further, the power supply device 302 is provided with a zero-cross switch type heater lamp drive circuit (not shown) consisting of, for example, a phototriac coupler and a triac, which drives the heater lamp 501 inside the fixing device 33. The above +24V is used as a driving power source for the light-emitting side LED of the coupler. In the heater lamp drive circuit with this configuration, as is well known, the light emitting side L
When the ED is turned on/off, the phototriac on the light emitting side is turned on/off at the zero cross point of the AC power supply, thereby turning on/off the triac, which is the main switch element in the next stage, and supplying the AC power Sl to the heater lamp 37a. It is designed to turn on or cut off electricity. And the light emitting side LED
A heater control signal S2 for turning on/off the heater control signal S2 is supplied from the engine control circuit 70 to the power supply device 302, and the thermistor 3 installed in the fixing device 37
The temperature signal detected at 7b is supplied to the engine control circuit 70.

Further, the cover switch 303 is turned off when the top cover (not shown) is rotated upward, and the cover switch 304 is turned off (not shown) when it is opened. Therefore, when the top cover or rear cover is opened, the switch 303.30
4 cuts off +24V, the semiconductor laser 90, mirror motor 60, high voltage power supply 305, main motor 307, solenoids 308 to 311, cooling fan 500, heater lamp 378, etc. stop operating, and the operator It is designed so that there is no problem even if you touch the inside of the device body l.

FIG. 4 is a block diagram showing the configuration of the engine control circuit 70. In the figure, CPU (CentralPr
A control unit 350 controls the entire engine control unit 300, and operates according to a control program stored in a ROM 351. RAM 352 is used as a working buffer for CPU 350. E2PRO
M353 stores the total number of prints, etc. The printer interface circuit 354 receives an interface signal S with the printer control circuit 71.
It is designed to mediate the delivery of 3 items. The laser modulation control circuit 355 controls the semiconductor laser 90 to be forced to turn on periodically in order to generate a laser light detection signal S4, which will be described later, and also controls the interface signal S.
3 modulates the semiconductor laser 90 according to the image data sent from the printer control circuit 71, and transmits the laser modulation signal S5 to the scanner control circuit 101.
It is designed to output to . The output register 356 is
Control signals S6, S7, S8, and S2 are output for controlling the mechanism drive circuit 306, the high voltage [1iij305], the scanner control circuit 101, and the heater lamp drive circuit, respectively. The voltage signals S9 and SIO generated by the thermistor 37b and the toner sensor 324 are input to the A/D converter 357, and the voltage values are converted into digital values. The input register 358 includes the paper empty switch 32.
0, manual feed switch 3211 paper ejection switch 49a,
49b, the mounting switch 323, the aligning switch 48, and the status signals S11, S12, S13, Si2, S15 from the paper detector 50.51.52, and the above +
A 24V on/off status signal SIB is input. Further, the internal bus 359 is connected to the CPU 350 RO
M351 RAM352E2PROM353, printer interface circuit 354, laser modulation control circuit 3
55, output register 35B, A/D converter 357
, and the input register 358.

The mechanism drive circuit 306 is provided with a drive circuit for driving various motors, solenoids, etc.
On/off is controlled by a binary control signal S6 output from the output register 356. That is, for example, each drive circuit is turned on when it is "1" and turned off when it is "0", and the pre-exposure device 21, main motor 307, solenoids 308 to 311, and cooling fan 500 are
V is energized or cut off. The scanner control circuit 101 is provided with a drive circuit for a semiconductor laser 90 and a mirror motor 60. The semiconductor laser 90 is turned on/off by a laser modulation signal S5 outputted from the laser modulation control circuit 355, and the mirror motor 60 is turned on/off by a control signal S8 outputted from the output register 356. It has become so. Further, a PIN diode is used in the laser light detection sensor 312, and when the laser light a passes through the laser light detection sensor 312, a current proportional to the energy flows therethrough. This current signal is the laser light detection signal S
4 and is sent to the laser modulation control circuit 355. Further, from the high voltage power supply 305, high voltages of the developing bias S20, band m522, and transfer S24 are supplied to a developing bias power supply section (not shown), a 4JL electric device 18, and a wire high voltage power supply section (not shown) of the transfer device 20, respectively. A signal is output. These on/off states are controlled by a control signal S7 of 1.0 output from the output register 35B.

As described above, within the engine control section 300, power is supplied to each electric circuit via the engine control circuit 70, and each section is controlled by a binary control signal output from the engine control circuit 70. It has become. This engine control section 300 and a printer control section 400, which will be described later, are connected by an interface signal S3.

Next, the configuration of printer control section 400 will be explained.

FIG. 1 is a block diagram showing the configuration of the main parts of the printer control section 400. In the figure, a CPU 401 controls the printer control unit 400 as a whole.

The ROM 402 stores a control program, and the CPU 401 operates according to this program. The ROM 402 also contains a password, a password, a margin, and a password to be checked when changing data.
Data regarding the paper P1 envelope A, such as the left margin and paper type, message information for notifying the operator, and a plurality of automatic switching ranges, that is, continuation contents, etc. are stored. The RAM 403 includes a host device 409
10 image data as received data sent from! ! A page buffer (receiving buffer) 403a is provided as a storage area, and the connection state of optional equipment and the set automatic switching range, that is, the continuation contents are stored.

The extended memory 404 has a large capacity and is used when the image data sent from the host device 409 is a large amount of data such as bitmap data and the RAM 403 cannot store one page of data. It's memory. The video RAM 405 stores image data developed into a bit image, and its output is supplied to a serial-parallel conversion circuit 406. The serial-parallel conversion circuit 406 is expanded into a bit image in the video RAM 405,
Image data sent as parallel data is converted into serial data and sent to the engine control circuit 70.

The host interface 408 is for exchanging data between the printer control unit 400 and the host device 4D9, which is composed of, for example, an electronic computer, a personal computer, or an image reading device.
, a flip-flop circuit (FF circuit) 408b, and an inverter circuit 408c.

That is, by transmitting received data a and a strobe signal indicating the transmission of the received data a from the host device 409 to the host interface 408, the received data a is supplied to the input/output port 408a, and the strobe signal is The signal is supplied to the input/output port 408a and the clock input terminal ck of the FF circuit 408b. The set input terminal S of this FF circuit 408b has the above-mentioned C
The reset signal d from the CPU 401 is supplied via the western bus 412 and the human output port 408a, and the reset signal d from the CPU 401 is supplied to the reset input terminal R via the internal bus 412 and the input/output port 408a. is supplied to the inverter circuit 408, and its reset output is supplied to the inverter circuit 408.
The data is sent to the host device 409 via C. The signal from this inverter circuit 408C is a busy signal C.

The host device 409 monitors the busy signal C from the host interface 40g, and when the busy signal C is off, the host interface 408 receives received data a and a strobe signal indicating the transmission of the received data a.
It is now sent to .

The engine interface 411 is the printer control circuit 7
1 and the engine control circuit 70 to mediate the reception of the interface signal S3. The connection circuit 413 cuts off the power and signal lines supplied to the IC card 517 when the IC card 517 is inserted into or removed from the connector (not shown). I due to the noise generated
This is to prevent data stored in the C card 517 from being destroyed.

The operation panel control circuit 407 performs controls such as displaying guidance messages on a liquid crystal display (not shown) of the operation panel 100. In addition, the internal bus 412 is
This is a bus that exchanges data between the PU 401 ROM 402, RAM 403, expansion memory 404, video RAM 405, operation panel control circuit 407, host interface 408, engine interface 411, and connection circuit 413.

The IC card 517 also includes a non-volatile memory, such as a static RAM with battery backup, an E2P
It is composed of a ROM SEPROM, a mask ROM, or the like. These IC cards 517 store, for example, character fonts, emulation programs, and the like.

Next, data transmission between the host device 409 and the printer control circuit 71 in the above configuration will be explained with reference to the flowchart shown in FIG.

That is, received data a from the host device 409 is sent to the RAM via the human output port 408a and the internal bus 412.
4031'), and is also supplied to the CPU 401 via the strobe signal output port 408a and the internal bus 412 (step 5TI). Then, the CPU 401 stores the received data a in the page buffer 403a (
Step 5T2). After this, the CPU 401 checks whether there is any free space in the page buffer 403a (step 5T3). If there is no free space and the page buffer is full, the CPU 401 sends the set signal d from the human output port 408a to the FF circuit 408b. Send to the set input terminal. As a result, F
The F circuit 408b is set, the reset output is inverted by the inverter circuit 408c, and the busy signal is turned on and output to the host device 409 (step 5T4). At this time, the CPU 401 remains in this state until the data processing progresses and the page buffer 403a becomes empty.

Also, if there is space in the reception buffer, the CPU 401
checks how much free space there is in the page buffer 403a. That is, it is checked whether the page buffer 403a is at the near end (step 5T).
5).

In the case of near-end, the CPU 401 sends the reset signal e from the human output port 408a only once to the reset input terminal of the FF circuit 408b. This results in
The FF circuit 408b is reset, and the inverter circuit 40
The busy signal from 8c is turned off (step 5T6)
. At this time, when the next data is sent from the host device 409, the FF circuit 408b is set by the strobe signal from the host device 409, and the inverter circuit 4
The busy signal from 08C turns on. That is, in this state, the busy signal is turned on/off for one data reception, so the operation is as shown in the timing chart shown in FIG. 6(a).

Furthermore, in step ST5, the page buffer 403a
is not at the near end, the CPU 401 sends the reset signal e from the input/output port 408a to the FF circuit 408.
Send it to the reset input terminal of b. As a result, the FF circuit 408b remains reset, and the busy signal from the inverter circuit 408C remains off (step 5T7).

That is, in this state, the busy signal remains off, so the operation is as shown in the timing chart shown in FIG. 6(b). This allows data to be sent from the host device 409 to the printer control circuit 71 at the highest speed.

This state continues until the page buffer 403a reaches the near end, and when the page buffer 403a reaches the near end, the busy signal is turned on/off every time data is received.

As described above, when transmitting data from a host device to a laser printer, the printer side determines whether there is space in the page buffer or whether the processing of previously received data has been completed. When a series of data can be continuously received, the busy signal that informs the host device whether or not data can be received is always turned off. When the laser printer is unable to receive a series of data, the busy signal is turned on and the data is returned to the original state again. It is designed to return to the transmission state for each data. As a result, if the busy signal is always off, the host device can confirm that it is always receiving data when it first checks the status of the printer, so it can transmit data at the host device's highest speed. It can be carried out.

As a result, data can be transmitted at high speed when transmitting data from the host device to the printer side.

Further, in the conventional procedure, data reception was not possible while the busy signal was on, but according to the present invention, data reception is possible. As a result, when an error occurs on the laser printer side, the busy signal must be turned on to prohibit data reception, but the host device's check of the busy signal is delayed and data is sent even when the busy signal is on. In this case, this data can be used as an H effect.

In addition, in the above embodiment, the case where the busy signal is kept off or the busy signal is turned off only once is changed depending on the free capacity of the page buffer, but this is not limited to this. A busy signal is generated depending on whether it is determined that the data processing speed of The off state of the switch may be changed.

[Effects of the Invention] As explained above, according to the present invention, it is possible to provide a data transmission system that can perform data transmission at high speed when transmitting data from a first device to a second device. .

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram showing the configuration of an engine control circuit, FIG. 2 is a configuration diagram showing the internal structure of a laser printer, and FIG. 3 is a main part of the engine control section. 4 is a block diagram showing the configuration of the engine control circuit, FIG. 5 is a flowchart for explaining data transmission operation, and FIG. 6 is for explaining the relationship between the strobe signal and the busy signal. This is a timing chart for 70...Engine control circuit, 71...Printer control circuit, 400...Printer control unit, 401...CP
U. 402-ROM, 403-RAM, 403a-
...Page buffer, 405...Video RAM, 40
B...Host interface, 408a...I/O port, 408b...FF circuit, 408C...Inverter circuit, 409...Host device, P...Paper.

Claims (1)

[Scope of Claims] A data transmission system for transmitting data from a first device to a second device, wherein the second device includes a receiving means for receiving data from the first device; processing means that performs processing according to the data received by the processing means; determining means that determines whether the processing by the processing means is finished; and a receiver that outputs reception permission to the first device according to the determination result of the determining means. permission output means, and the first device comprises data output means for outputting data to the second device in response to reception permission from the second device. .