JP2886241B2 - Image forming system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to various printer systems such as laser printers, LED printers, liquid crystal shutter printers, ink jet printers, and high-performance digital copiers and high-performance fax machines. The present invention relates to an image forming system.

[Conventional technology]

2. Description of the Related Art In recent years, image forming apparatuses such as laser printers have tended to be systematized so as to meet various demands, and receive character information or image information from a host system such as a word processor, office computer, personal computer, etc. An image processing unit for generating information; an image forming unit for receiving image information from the image processing unit to form an image on a recording medium; each being detachable from the image forming unit, for feeding and discharging the recording medium; Image forming systems are being constructed by connecting various types of additional devices to be sent or conveyed via respective interfaces.

In some cases, the host system has a function corresponding to the image processing unit. In such a case, the image forming unit receives image information directly from the host system and forms an image on a recording medium.

In such an image forming system, the problem is what to do when an error occurs in the image forming unit or various additional devices.

Therefore, as shown in, for example, JP-A-62-102330, an error occurs in the printer (in this case, a data error).
Conventionally, there has been a technique for allowing a user to select whether or not to continue printing after the occurrence of a printing error.

However, this only refers to an error in which printing can be continued from the point of view of image formation.

In other words, the error received from the host by the image processing unit was incorrect, or the error occurred when the print area laid out by the image processing unit and the size of the recording medium actually used were different. Necessary errors, for example, errors such as paper jam, cover open, paper feed paper end, and paper discharge full have not been taken into account.

In addition, the present applicant has previously proposed (Japanese Patent Application No. 63-287147).
), A command queue is provided in the image forming unit, and a specific command (instruction group) among the commands sent from the image processing unit is stored in the command buffer, and these commands are sequentially specified. Another technique was to execute these instructions sequentially.

For example, the image forming unit receives commands related to image formation (paper feed command, paper discharge command, paper feed tray selection command, paper discharge tray selection command, mode set command, etc.) sent from the image processing unit. Are temporarily stored in their own command queue buffers as shown in FIG. 23, and are sequentially executed.

In such a case, unless an error has occurred in the image forming section and various additional devices, the command in the command buffer is always executed.

[Problems to be solved by the invention]

Such an image forming system has no problem as long as no error exists in the system and image formation is performed without any trouble.

However, if an error requiring repair during execution of an instruction, for example, an error such as a paper jam, an apparatus cover open, a paper feed tray paper end, or a discharge tray overflow, processing after the error recovery becomes a problem. I was

For example, as shown in FIG. 24, two paper trays ST (#
1, # 2), in an image forming system having one sheet ejection tray ET and no additional device, when printing is performed in a link tray mode (described later), the image processing unit usually has a capacity of one page. As soon as the image is ready, a feed command and a print command are sent to the image forming unit.

Then, as shown in FIG. 25, when a paper end occurs as a result of the image forming unit executing the paper feed command i in the command buffer, the image forming unit immediately generates a paper end state (error). To the image processing unit, and waits for execution of the next instruction (enters a wait state after executing the factor instruction i).

If not in the link tray mode, the image processing unit prompts the operator to store sheets in the paper feed tray i via the operation panel. In the case of the link tray mode, the command queue buffer of the image forming unit is temporarily stopped. After clearing (paper feed command i + 1 and subsequent ones are cleared), another paper feed tray selection command is sent again, and then paper feed and print commands after i + 1 are sent.

However, conventionally, when the error state of the image forming unit is canceled (here, the error is canceled by storing sheets again in the sheet feeding tray # 1), the image forming unit automatically issues a command buffer. The execution of the instruction in was restarted.

Therefore, if the processing on the image processing unit side is delayed and the queuing buffer clear instruction is issued too late, the paper feed instruction i + 1 is executed, and the paper is additionally fed. Was.

As a result, a disadvantage such as missing image or missing page has occurred which is extremely unfavorable as a printer.

Further, when a paper jam occurs, when the image forming unit is operating in the jam backup mode (described later), the image forming unit automatically cancels the next jam in the command buffer after the jam is released. Since the command was executed, the number of fed sheets could not be counted normally, and a normal jam backup could not be performed.

Also, when operating in the paper output link tray mode,
If a phenomenon occurs such that the output tray that has once overflowed is lost due to overflow (the description will be described later), the image processing unit attempts to change the output tray, but the image forming unit attempts to change the output tray. There was also a problem that the paper was discharged to the current paper discharge tray without permission.

The present invention has been made in view of these problems, and provides a highly reliable image forming system that can solve all of the above problems and can appropriately perform processing after an error has occurred. The purpose is to:

Here, the link tray mode, the jam backup mode, and the discharge tray overflow will be briefly described.

<Link Tray Mode> In an image forming system having a plurality of paper feed trays, a recording medium of the same size is stored in each tray, and first, paper is fed from the first paper feed tray # 1 (see FIG. 24). To execute image formation. In the continuous printing process, as soon as the first paper feed tray # 1 reaches the paper end (no recording paper), the paper feed operation is immediately performed from the other paper feed tray # 2 to execute image formation.

While paper is being fed from the paper feed tray # 2, the operator can store recording paper in the first paper feed tray # 1.

Then, when the paper feed tray # 2 reaches the paper end, the paper feed tray (# 1 or # 3) containing the recording paper at that time is immediately selected, and the image formation is continued continuously again.

As described above, as soon as the currently fed paper feed tray reaches the paper end, the operator selects another paper feed tray containing the recording paper and executes image formation, so that the operator can print the recording paper. Printing can be performed continuously during the storing operation, and the actual printing speed is increased. Such control is called a paper feed link tray mode.

Similarly, if the currently selected paper output tray overflows (paper full),
The control for immediately selecting another discharge tray and continuing the discharge operation is called a discharge link tray mode.

<Jam Backup Mode> Generally, when a jam occurs somewhere in the image forming unit, the image of the recording paper having the jam is lost.

For example, in an image forming system as shown in FIG. 26,
Assuming that a recording paper j is now jammed, the recording paper j-1 can be completed until the paper is ejected, but the recording paper j + 1 (the recording paper that is just forming an image) must be stopped. . Therefore, the images on the recording papers of j and j + 1 are lost.

Therefore, when the image forming unit is operating in the jam backup mode, the image processing unit clears the paper feed and print commands once sent to the image forming unit (the command clear buffer clear command is transmitted). Again, a feed and print command corresponding to the j, j + 1 recording paper is sent out again to execute image formation and secure an image.

As a result, a series of images is formed normally without loss.

<Discharge Tray Overflow> As shown in FIG. 27, in a system in which a tray overflow sensor OFS having an actuator ACT is provided above the discharge tray ET, the recording paper discharged onto the discharge tray ET is When it becomes full, the actuator ACT is pushed upward by the recording paper P at its uppermost position, and the tray overflow sensor OFS (photo interrupter) detects it and notifies the discharge tray overflow state.

By the way, the recording paper P generally undergoes a curl phenomenon after the fixing step as shown by a solid line in FIG. However, after a certain period of time after the discharge, this curl is naturally corrected and flattened as shown by the broken line in FIG.

Therefore, a phenomenon often occurs that the overflow state is naturally eliminated after the overflow state is once detected on the paper discharge tray ET.

[Means for solving the problem]

As shown in FIG. 1, the present invention comprises an image processing section C for receiving character information or image information from a host system A to generate image image information, and an image processing section C for receiving image image information from the image processing section C, and An image forming section D for forming an image on the image forming section D, and various additional devices E which are detachable from the image forming section D and feed, convey, or discharge the recording medium, respectively. D sends various commands relating to image formation to the image forming unit D, and stores the specific commands among the various commands in a buffer (queue buffer) F therein, and sequentially stores these specific commands. In the image forming system B that executes and forms an image,
In order to achieve the above object, when an error occurs in the image forming unit D or in the various additional devices E, the execution of the instruction stored in the buffer F is interrupted, and after the error is released, Means is provided for restarting execution of the command by receiving a restart command from the image processing unit C.

Further, when the image processing unit C does not set a specific operation mode, the image processing unit C sets the image forming unit D to restart the execution of the command immediately after the error is cleared (restart selection). (Corresponding to the means G).

Further, it is preferable that the image processing section C has means for transmitting a command to clear the command stored in the buffer F to the image forming section D before transmitting the restart command.

[Action]

According to the present invention, when an error occurs in the image forming unit or the additional device, the image forming device interrupts the execution of the instruction stored in the buffer and automatically performs the image forming operation even if the error is released. Instead of restarting, after receiving the restart command from the image processing unit, the execution of the command is restarted to restart the image forming operation. Therefore, for example, it is possible to prevent a problem that an image is lost or a page is missing in the link tray mode. In addition, it is possible to prevent a problem at the time of detecting an overflow due to the curl of the discharged sheet and a malfunction in the jam-backup mode.

Also, when a specific operation mode such as the link tray mode or the jam backup mode is not set, the image processing unit sets the image forming unit to restart the execution of the above command immediately after the error is cleared. By doing so, the procedure of communication between the image processing unit and the image forming unit relating to processing after error recovery is simplified, and the interruption time of image formation is also reduced.

Further, when operating in the jam backup mode, the image processing unit transmits a command to clear the command stored in the buffer F to the image forming unit before transmitting the restart command. By clearing the previously transmitted command relating to image formation and transmitting a print command relating to the next recording sheet again, occurrence of image omission can be reliably prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

System Configuration Example FIG. 2A is a block diagram showing a basic system configuration example of an image forming system to which the present invention is applied.

The image forming system includes an image forming apparatus main body 4 that receives character code information or image image information from a host system 1 and forms an image on a recording medium, and includes five detachable image forming apparatus main bodies 4 respectively. Additional device 5A
To 5E.

That is, as the additional devices, a multi-stage paper feeding device 5A and a large-volume paper feeding device 5B, which are additional paper feeding devices, an inverted paper discharging device 5C and a large-volume paper discharging device 5D, which are additional paper discharging devices, and an additional recording medium transport device. The two-sided conveyance device 5E is connected to the image forming apparatus main body 4
Are mechanically connected to each other, and they are all connected by a common signal line (serial bus) SB.

The image forming apparatus main body 4 and each of the additional devices 5A to 5E are provided with serial communication sections 4a and 5a to 5e as communication means for performing serial communication via signal lines SB.

Further, a command issuing unit is provided in the image forming apparatus main body 4.
4b, the command issuing means 4b converts a command including an identification code for individually specifying each of the additional devices 5A to 5E and a command including a common identification code for specifying all of the additional devices as necessary. It is issued and transmitted to each of the additional devices 5A to 5E via the signal line SB by the serial communication unit 4a.

Therefore, the image forming apparatus main body 4 can usually specify and control each of the additional devices 5A to 5E individually, and if necessary, for example, a serious error occurs in the system, For example, when not stopping all mechanical operations in the system, an emergency stop command is issued to each of the additional devices 5A to 5E at the same time by issuing and transmitting a command including a common identification code specifying all the additional devices. Etc. can be transmitted and executed.

Here, a communication protocol between the image forming apparatus main body 4 and each of the additional devices 5A to 5E will be briefly described.

Communication from the image forming apparatus main body to the additional apparatus is performed by transmitting a command, and communication from the additional apparatus to the image forming apparatus main body is performed by transmitting a response.

As shown in FIG. 2B, one command is composed of an operator and an argument each having 8 bits, and transmits the operator first and then the operator.
Top three bits b ₇ ~b ₅ of Agiyumento is always "111".

Then, the normal command, as shown in FIG. 2B (a), placed in an identification code (ID) of the adding device for specifying the upper three bits b ₇ ~b ₅ of the operator as the communication partner, b ₄ ~b ₀ Is a code indicating the type of instruction.

Here, each of the additional devices 5A to 5E in the system of FIG.
Are defined as follows, for example.

Multi-stage paper feeder 5A: 000 (IN # 1) Large-volume paper feeder 5B: 001 (IN # 2) Double-sided conveyance device 5E: 010 (DPX # 1) Reverse paper-ejecting device 5C: 100 (OUT # 1) Paper device 5D: 101 (OUT # 2) The upper two bits of the three-bit identification code indicate the type of additional device (type: paper feed, transport, discharge), and the lower one bit is the device number (#). 1 or # 2), which is clearly indicated in parentheses.

FIG. 2B (b) shows a configuration of a command (hereinafter, referred to as "global ID command") including a common identification code (hereinafter, referred to as "global ID address") for specifying all the additional devices.

The global ID command, and the upper three bits b ₇ ~b ₅ of the operator, a global ID address "110",
In b _{4 to} b ₀ , a code indicating the type of instruction, for example, in the case of an emergency stop instruction, “01111” is entered for b _{4 to} b ₀ .

When each of the additional devices 5A to 5E receives this global ID command in its respective serial communication unit, it recognizes that it has been specified and immediately executes the command without returning a response.

An example of using the global ID command is as follows.

(A) When performing system initialization (initialization operation and self-diagnosis).

(B) When the paper size is set in each additional device when an image forming operation is performed by selecting a paper feeding device that cannot detect the paper size by itself.

(C) When it is necessary to urgently transmit information to all the additional devices (for example, when transmitting an emergency stop command when a paper jam occurs).

Logical ID and Device ID FIG. 3 is a block diagram showing an example of a system configuration in which the scalability of the image forming system according to the present invention is further enhanced, and portions corresponding to those in FIG. Description is omitted.

The image forming system includes an image forming apparatus main body 4 that receives character code information or image image information from a host system 1 and forms an image on a recording medium, and includes seven detachable image forming apparatus main bodies 4 respectively. Additional device 5A
The system is configured by ~ 5G.

That is, a multi-stage paper feeder 5F and a multi-stage paper discharge device 5G are added to the image forming system of FIG. 2A as additional devices, and the image forming apparatus main body 4 and each of these additional devices 5A to 5G are all shared signals. Connected by line SB. It is possible to add more additional devices as indicated by the broken lines.

The image forming apparatus main body 4 according to this embodiment includes:
A maximum of two additional paper feeders, a maximum of two additional paper discharge devices, and a maximum of one additional double-sided conveyance device can be simultaneously controlled.

Here, being able to control at the same time means a state satisfying all of the following.

○ Direct communication enables processing of execution commands, inquiry commands, selection commands, etc.

○ Feeding, conveying, and discharging of recording media can be executed by commands.

○ It can be selected as the transport path of the recording medium

Therefore, the image forming apparatus main body 4 has six types of codes as control identification codes (hereinafter, referred to as “logical (logical) IDs”). This corresponds to the identification code (ID) of each additional device described above.

That is, all the additional devices (option units) are classified into three types of unit types, namely, a paper feeding device, a paper discharging device, and a transporting device.
ID is prepared.

Additional paper feeder (IN # 1): 000 Same (IN # 2): 001 Additional transporter (DPX / INP): 010 Same (DPX / OUT): 011 Additional paper ejector (OUT # 1): 100 Same ( OUT # 2): 101 This logical ID is a 3-bit code, of which the upper 2 bits are a unit type code for identifying IN, OUT, DPX, and the lower 1 bit is # 1 or # 2. It is a code for identifying a number (in the case of an additional transport device, that is, a duplex transport device: DPX, whether to use it as an input unit (INP) or an output unit (OUT)).

The image forming apparatus main body 4 has a serial communication function of transmitting a command including the logical ID to the signal line SB, and all of the internal image processing unit, the image creating unit, and the external host system normally operate the logical ID. Using each additional device
Identify 5A-5G.

On the other hand, each of the additional devices 5A to 5G has a unique identification code (hereinafter, referred to as “device ID”), and its device ID.
Is transmitted to the signal line SB.

In addition, each unit has its own unit type, that is, a paper feeding device (IN), a paper discharging device (OUT), and a double-sided conveying device (DP).
X) is stored as a two-bit code like the unit type code of the logical ID.

If the device ID is given by a 4-bit code for each unit type, 16 units can be identified for each unit type, for a total of 48 units.

In this embodiment, device IDs are assigned as follows.

Multi-stage paper feeder 5A: (IN) 0000 Multi-stage paper feeder 5F: (IN) 0001 Large-volume paper feeder 5B: (IN) 0010 Reversing paper ejection device 5C: (OUT) 0000 Multi-stage paper ejection device 5G: (OUT) 0001 Mass discharge device 5D: (OUT) 0010 Double-sided transport device 5E: (DPX) 0001 In addition, IN, OUT, DPX in parentheses is actually a 2-bit unit type code and is only for each additional unit (option unit). The device ID is stored separately, and only the 4-bit code after that is the device ID.

Therefore, in the image forming apparatus main body 4, an additional device in the same unit type is designated (assigned) to each logical ID, and the device ID is stored in a table in the memory, for example, as shown in the following table. .

On the other hand, each of the additional devices 5A to 5G has its own unit type code (IN, DPX, OUT identification code) and a memory for storing the device ID, and a memory when the logical ID is assigned (specified). And a memory for storing a logical ID.

In this way, the six logical IDs and the device IDs of the additional devices respectively assigned thereto (however, DPX
・ The device ID of the same transport device for both sides is used for INP and DPX / OUT
The image forming apparatus main body 4 can specify and control the assigned additional device only by the logical ID.

In FIG. 3 and the above-described example, the multi-stage paper feeder 5A is placed in IN # 1 of the logical ID (indicated with Log in FIG. 3) as the additional paper feeder, and the large-volume feeder 5B is placed in IN # 2. Inverted paper output device 5C, OUT # 2 to OUT # 1 of logical ID as additional paper output device
To the DPX (I)
NP and OUT) are assigned to the double-sided transfer device 5E.

In FIG. 3, the assigned additional device is indicated by a double-lined frame. Therefore, the image forming apparatus main body 4 can simultaneously control the five additional devices 5A to 5E.

However, since this assignment state can be changed as needed, it can be used even when other additional devices, that is, the multi-stage paper feeding device 5F and the multi-stage paper ejection device 5G or more additional devices are added. , You can make them available.

In addition, between the image processing apparatus and the image forming apparatus in the additional forming apparatus main body 4, and between the image forming apparatus main body 4 and each additional device 5A.
The communication protocol for serial communication between ~ 5G provides two levels of commands.

One of them is a basic command. When the image forming system includes two or less additional paper feeding devices, two or less additional paper discharging devices, and one or less double-sided conveyance device, a logical command is issued. The basic command, which is a command for handling only the additional device registered in the ID, can include all system functions.

Thus, an image forming system in which all system functions can be controlled by a basic command is referred to as a basic system. In this system, the code number of the device ID may be the same as the code number of the logical ID. The example of the system configuration shown in FIG. 2A corresponds to this basic system.

The other is an enhancement command (extended command). If the image forming system has three or more additional paper feeders, three or more additional paper discharge devices, or two or more double-sided conveyance devices, the three commands are used. The additional paper feeding device or additional paper discharging device and the second and subsequent double-sided conveying devices assign the device ID to the same unit-type logical ID using the enhance command, and thereby, This makes it possible to control paper feeding, paper discharging, double-sided conveyance, and the like.

Laser Printer System An embodiment in which the present invention is applied to a laser printer system will be described below.

FIG. 4 is a block diagram showing a schematic configuration of the laser printer system, and portions corresponding to FIGS. 2A and 3 are denoted by the same reference numerals.

This laser printer system has a host system 1
(Corresponding to A in FIG. 1), a printer as an image forming apparatus main body including a controller 2 (corresponding to C) and a print engine (hereinafter simply referred to as “engine”) 3 (corresponding to D). Main body 4 and additional device described above
Various additional devices such as 5A to 5G (hereinafter also referred to as "option unit") 5 (also equivalent to E), a host interface (hereinafter abbreviated as "host I / F") for connecting them, and a laser printer -It is composed of a video interface (hereinafter abbreviated as "LPVI") and an engine option interface (hereinafter abbreviated as "EOI / F").

The host system 1 is an information processing device such as a word processor, an office computer, or a personal computer for transmitting character information or image information.

The controller 2 is an image processing unit that receives character information and image information from the host system 1 and generates image image information (video data) for each page of a print sheet.

The engine 3 is an image forming unit that prints the image information generated by the controller 2 on paper.

The host I / F is an interface for connecting between the host system 1 and the controller 2, and RS232C, Centronics I / F and the like are well known.

The LPVI is a standard interface that connects the controller 2 and the engine 3 that constitute the printer body 4, and unifies the hardware of the video interface that has been individually determined for each engine (for each model) in the past. It is not affected by the function.

The EOI / F connects the engine 3 and the various option units 5 by the above-described common signal line (serial bus), and transmits a command including the above-described logical ID from the engine 3 so that the engine 3 can use the ID. This is a standard interface for serial communication by the specified option unit returning a response.

 FIG. 5 shows a hardware configuration of the controller 2.

The controller 2 includes a CPU 20 and a program RO as shown in the figure.
M21, RAM22, font ROM23, nonvolatile RAM24, operation panel 2
5, a scaling unit 26, an option interface 27, a video control unit 28, an engine interface 29, and the above-described host interface 54 and a controller-side part of the LPVI, all of which are connected by a CPU bus.

The CPU 20 is a central processing unit for controlling the whole of the controller 2, and uses a general 16-bit or 32-bit micro computer.

The program ROM 21 stores microcode (program) for controlling the CPU 20.

The RAM 22 is a large-capacity random access memory, and is mainly used for the following purposes.

(A) System memory (b) Input buffer (c) Page buffer (d) Font file (e) Macro file (f) Image file (g) Print control file (h) Video buffer FIG. 6 shows the flow of data processing. And the relationship between each buffer and file in the RAM 22.

Information sent from the host system 1 is stored in the input buffer 22b via the host interface 54.

The data stored in this input buffer 22b is
The data is extracted by the data processing unit 201 and registered in one of the page buffer 22c or the font file 22d, the macro file 22e, the image file 22f, and the print control file 22g according to the type of data.

That is, the print sequence control data (designation of the paper transport path, the number of prints, etc.) is stored in the print control file 22g, the page layout information (the relation between the print data and the print position) is stored in the page buffer 22c, and the image information is stored in the image file 22f. The download font is registered in the font file 22d, and the overlay information and the like are registered in the macro file 22e.

The image information processing unit 202 includes an image file 22f and a font file 22d in accordance with the contents of the page buffer 22c.
Then, the contents of the font ROM 23 are expanded into the video buffer 22h through the scaling unit 26.

When the development of the print data for one page is completed in the video buffer 22h, the print control unit 203 activates the engine 3 via LPVI according to the contents of the print control file 22g, and when the engine 3 reaches the image recording timing, the video buffer 22h. LPVI with expanded video data
To the engine 3 via

The engine 3 prints the video data sent through the LPVI on a sheet.

Returning to FIG. 5, the font ROM 23 stores font data for converting character information sent from the host system 1 via the host interface 54 into image information.

The nonvolatile RAM 24 is a memory for storing information for controlling the operation state of the printer after the power is turned on,
The following items are mainly stored.

(A) Printing direction (b) Font (font) (c) Character size (d) Line spacing (e) Paper feed port (f) Paper discharge port (g) Host interface (h) Paper feed link tray mode (i) ) Discharge link tray mode (j) Jam-backup mode The contents stored in the nonvolatile RAM 24 are updated from the operation panel 25.

FIG. 7 shows an example of the appearance of the operation panel 25. An operation of updating the storage content of the nonvolatile RAM 24 by using the operation panel 25 is called a mode set.

The operation panel 25 has an LCD display 250 for displaying the status of the printer in text as well as the contents of the mode set, a power LED 251 that is lit when the power is turned on, an online LED 252 that indicates the online status of the printer, and a lit when the printer is abnormal. Or blinking attention LED 253, data LED 254 indicating that there is print data in the printer, online switch 255 for switching online / offline of the printer, and printing data in the printer when data LED 254 is on. FormFeed
It comprises a switch 256, a test switch 257 for activating the self-diagnosis test function of the printer, etc., a reset switch 258 for resetting the printer, and switches 25A, 25B, 25C, 25D for mode setting operation.

The contents of the mode set arrange the set items in a hierarchical manner.

Then, in the offline state, the up arrow mode switch
By pressing 25A, the mode is set and the first item is selected and displayed. If you want to select another item,
When the right arrow switch 25B or 25C is operated, each time the switch is pressed, the display of the set item changes cyclically.

When the desired set item is displayed, enter switch 25
Pressing D displays the mode selection for the next level.

Then, when a desired mode is selected by the left and right arrow switches 25B or 25C and the down arrow enter switch 25D is pressed, it is registered in the nonvolatile RAM 24. That is, by pressing the enter switch 25D at the lowermost layer, the registered contents of the nonvolatile RAM 24 are updated.

By the mode setting operation on the operation panel 25, the above-mentioned "sheet feed link tray mode", "discharge link tray mode", and "jam back-up mode" can be set.

These modes can also be set by a command from the host system 1 to the controller 2.

Returning to FIG. 5, the scaling unit 26 is a scaling unit for scaling the image information to an optimum size in accordance with the resolution of the engine 3.

The host interface 54 is an interface for connecting the host system 1 and the controller 2, and prepares two of a Centronics-compliant parallel and an RS-232C, and selects them by operating the operation panel 25 described above.

The option interface 27 is an interface when a font or a program is externally supplied to extend the function. In this example, two IC cards 6 can be handled.

The video control unit 28 controls the video buffer 22h in FIG.
Video data stored at a bus width of 20 (16 bits or 32 bits) is converted into serial data or 8-bit parallel data, and sent to the engine 3 via LPVI.

The engine interface 29 has a serial communication (transmission / reception) function of detecting the state of the engine by a bidirectional serial signal via the LPVI and transmitting a command to control the engine.

Here, the LPVI signal is shown in FIG. The signal includes an image signal system, a control signal system, and a power supply.

The image signal system is / WCLK, / WDATA, / LSYNC, / LGATE, / FGATE
These are the five types of signals.

The control signal system is four kinds of signals of / PETXD, / PERXD, / PECTS, / PEDTR, and the power supply is two kinds of + 5V and GND.

Here, "/" added to the front of each signal name indicates negative logic (low active) and is shown with an overline in FIG.

 Hereinafter, each signal will be briefly described.

(A) / WCLK: Clock for synchronizing image data from print engine. The image is printed by transmitting the image data (/ WDATA) in synchronization with the fall of this signal. Low level is black.

(B) / WDATA: image data sent from the video signal control unit 28 in FIG.

(C) / LSYNC: Line synchronization signal indicating the start of each scan line.

 Synchronizes with the falling edge of the / WCLK signal.

(D) / LGATE: a signal indicating the effective image area of each scan line.

 Synchronizes with the falling edge of the / WCLK signal.

(E) / FGATE: A signal indicating the effective image area in the paper feed direction. Synchronizes with the fall of the / LSYNC signal.

(F) / PETXD: status signal for notifying the controller of the engine status from the engine.

(G) / PERXD: Command line from the controller to the engine.

(H) Indicates the ready of the / PECTS: / PETXD signal. When this signal is at a low level, it is possible to send a status from the engine to the controller.

(I) Indicates the ready of the / PEDTR: / PERXD signal. When this signal is at a low level, a command can be sent from the controller to the engine.

(J) + 5V: + 5V power supplied from the engine.

(K) GND: Ground (Earth) FIG. 9 shows the relationship between the print area and the image signal.

Reference numeral 7 denotes an effective printing area, 8 denotes an image area printed by the / WDATA signals 8a and 8b, and 9 denotes an image area printed by the / WDATA signals 9a and 9b.

Next, an example of the configuration of the engine will be described with reference to FIGS. 10 and 11. FIG.

FIG. 10 is a schematic diagram of an engine main body constituting the mechanical part of the engine 3 of the above-described laser printer system, and the mechanical parts of various option units connected thereto.

Reference numeral 10 denotes an engine body, including a photosensitive drum 101, a charging charger 102, a light (laser) writing unit 103, a developing device 104, a transfer separating charger 105, a cleaning unit 106, a fixing unit 107, and a pair of registration rollers 108. And a drive motor and a drive mechanism for the rollers.

Reference numerals 11 and 12 denote paper cassettes (trays) which are directly mounted on the engine body 10 and can normally store 100 to 200 sheets of paper. It is also possible to insert a multi-stage paper feeding unit corresponding to the above-described multi-stage paper feeding device 5A, 5F having a multi-stage paper feeding cassette (tray) into the two paper feeding cassette insertion openings of the engine body 10. it can.

Reference numeral 13 denotes a reversing device for switching a paper discharge path, which corresponds to the above-described reverse paper discharge device 5C, and has a paper discharge path of its own upper paper discharge tray 14,
It can be switched to any of a mail box (multi-stage paper discharging device) 15, a double-sided paper unit 16, and a large-volume paper discharging unit 18.

Further, other than the upper discharge tray 14, a sheet which is turned upside down can be supplied to each unit. Of course, non-reversed paper can also be supplied. Therefore, face-up discharge and face-down discharge can be arbitrarily selected by using this function.

15 is a mail box having a large number of output trays 15a,
It corresponds to the above-described multi-stage paper ejection device 5G, and can select an arbitrary paper ejection tray according to an instruction from the controller 2.

Reference numeral 16 denotes a double-sided unit serving as a re-feeding unit for double-sided printing, which corresponds to the above-described double-sided conveying device 5E. Supplied and from here the engine body 10 again
The sheet is fed to the printer and printed on the other side, whereby double-sided printing is performed.

The double-sided unit 16 used in this embodiment is
Paper path 161 without stopping supplied paper
And a second transport path for transporting the supplied sheets to a stacker 162 sequentially and holding the required number of sheets, stacking the required number of sheets, and sequentially transporting the sheets to the sheet supply side. It has a transport path.

Reference numeral 17 denotes a large-volume paper feeding unit corresponding to the above-described large-volume paper feeding device 5B, which can store about 2000 sheets.

Reference numeral 18 denotes a large-volume paper discharging unit corresponding to the above-described large-volume paper discharging device 5D, which can store about 2,000 or more sheets.

By setting the number of sheets stored in the large-volume paper discharging unit 18 to be larger than the number of papers stored in the large-volume paper feeding unit 17, all the sheets supplied from the large-volume paper feeding unit 17 can be discharged.
18 can be collected.

Reference numeral 19 denotes a printer table on which the engine body 10 and its option unit are mounted. The inside of the printer table is used as a storage space 19a for the controller 2 described above.

Engine unit 10 and option unit (reversing unit 13, mail box 15, double-sided unit 16, high-volume feeding unit 17,
The mass discharge unit 18) is connected by the aforementioned engine option interface (EOI / F).

Further, it is possible to configure a system by omitting a part of these units, or replacing or adding various option units other than these units with the above-mentioned units.

Here, a printing operation by each unit in the engine body 10 will be briefly described.

As the paper supply source, one of the upper paper feed cassette 11, the lower paper feed cassette 12, the high-volume paper feed unit 17, and the duplex paper unit 16 (only during refeeding) of the engine body 10 is selected and the paper is supplied. Then, it stands by at the position where it is held between the registration roller pair 108.

On the other hand, the photosensitive drum 101 rotates in the direction indicated by the arrow, and the laser beam modulated according to the video signal by the optical writing unit 103 is mainly applied in the drum axial direction on the surface charged by the charging charger 102. Exposure is performed by irradiating while scanning to form a latent image.

The latent image is developed with toner from the developing device 104,
The toner image is transferred to a sheet fed to the image transfer unit at a predetermined timing by a pair of registration rollers 108 by a transfer separation charger 105, and the transferred sheet is separated from the surface of the photosensitive drum 101. Let it.

The sheet on which the image has been transferred is conveyed to the fixing unit 107, where the sheet is heated and fixed by a fixing roller and a pressure roller heated to a certain temperature, and then sent to the reversing unit 13.

The sheet discharged from the engine body 10 and sent to the reversing unit 13 is sent out from one of the three outlets A, B, and C at the upper side, the side, and the lower side. It is discharged to the mail box 15 and the duplex unit 16.

If the paper is ejected to the duplex unit 16,
The sheet is re-supplied to the engine body 10 through one of the second conveyance paths, or is discharged to the mass discharge unit 18.

Next, FIG. 11 shows a block configuration of the engine main body 10 and an engine control section (engine driver) 30 for controlling the above-mentioned option units connected thereto.

The CPU 31 is a central processing unit that controls the engine control unit 30 as a whole, and uses a general-purpose 8-bit microcomputer.

Reference numeral 32 denotes a program ROM, which stores a microcode for controlling the sequence of the engine body 10 and the connection with the controller 2 and each of the above-mentioned units (engine option units).

33 is for storing control data and engine status, etc.
This is a RAM, and a part of the memory area of the RAM 33 is used as a command buffer described later.

Reference numeral 34 denotes an interval timer for creating a basic time for controlling the sequence of the engine.

35 is engine option interface (EOI /
F), which is a serial interface for connecting the inverter unit 13, the mail box 15, the double-sided unit 16, the large-volume paper feeding unit 17, the large-volume paper ejection unit 18 and the like, which are option units, by a common line. Therefore, it has a serial communication function.

Each option unit has the device described above.
When communication is performed between the engine control unit 30 and each of the option units 13, 15 to 18, the other unit is specified by transmitting a command to which a logical ID to which the device ID is assigned is added. , Receive a response from the unit.

Reference numeral 36 denotes a controller interface, which receives a command from the controller 2 via the LPVI and informs the controller 2 of the state of the engine 3.

An optical control unit 37 receives the image signal (video data) sent from the controller 2 via the LPVI and controls the optical writing unit 103.

Reference numeral 38 denotes an A / D converter, which receives an analog signal from a thermistor (temperature sensor) of the image forming / paper transport unit 100 of the engine body 10 after being amplified by an operational amplifier 41, and which can be processed by the CPU 31. To a digital signal as follows.

The above-mentioned thermistor is for grasping the temperature condition in each unit and the like in the machine, and is provided at several places in the machine.

Reference numeral 39 denotes an I / O port, which drives a motor, a plunger, a clutch, and the like in the image forming / paper transport unit 100 of the engine body 10 via a driver 42 and a driver 43, and applies a high voltage to various chargers. And a signal from a sensor or a switch for detecting the state of the engine body 10 is amplified to a logical level via an amplifier 44.

These units are connected to the CPU 31 by a CPU bus 40 including a data bus, a control bus, and an address bus.

Next, communication between the controller 2 and the print engine 3 will be described.

First, the communication conditions between the controller and the print engine are as follows.

1. Interface: Asynchronous serial I / F 2. Communication speed: 9600 baud 3. Parity bit: None 4. Stop bit: 1 Communication between controller and print engine via LPVI 4 types of signal / PETXD, / PERXD, / PEC
This is done by TS and / PEDTR.

Next, a communication protocol between the controller and the print engine will be briefly described.

Communication between the controller 2 and the print engine 3 is performed by transmitting a command from the controller to the print engine, receiving the command, and returning a response to the controller.

Each command is composed of a 1-byte argument and an operator. As shown in FIGS. 12A and 12B, the most significant bit of the argument is always "1".
The most significant bit of the operator is always "0".

The command sends the argument first and the operator later.

Arguments can also be omitted, in which case the print engine must correctly recognize the command without the argument.

If a command consisting of an Argument and an Operator (eg, a "Status Request" command) is issued by the controller without an Argument, the previous Argument of the same command is effectively in effect.

When the print engine receives the command, if there is no valid argument, the print engine defaults to a virtual argument.

The response is to send the information requested by the received command from the print engine to the controller.

The length of each response is 1 byte, and the most significant bit is "0" as shown in FIG. 12 (c). However, in the case of a response to the "illegal command" shown in FIG. 9D, all bits are "1".

Event reports show events (options such as occurrence of jams and supply shortage) in the option unit and print engine.
When an error occurs, the print engine sends information not requested to the controller as a response.

Each event report includes one as shown in FIG.
It has a length of one byte and its most significant bit is "1".

This event report generation is enabled / disabled by the controller using the 'ETB' command.

In this embodiment, the types of commands transmitted by the controller are as follows, and there are 13 basic commands and 3 enhance commands.

<Basic command> 1. Status request 'ENQ' 2. Inquiry input tray condition 'SI' 3. Inquiry output tray condition 'SO' 4. Inquiry paper size of input tray 'EM' 5. * Feed start 'FF' 6. * Print start 'VT' 7. * Input tray select 'DC1' 8. * Output tray select 'DC2' 9. Event report enabled 'ETB' 10. * Print engine mode set DC4 '11. * Paper size set' DC3 '12. Inquiry exited paper ID (ACK) 13. Reset' CAN '<Enhance command> 14. Assign device ID' FS '15. Inquiry assigned Device 'GS' 16. Inquiry Communication Active Device ID 'RS' Of the above commands, the command marked with * is the The command is stored in the command queue secured in the RAM 33 in the engine control unit 30 shown in FIG. 11 and is sequentially executed.

However, as for the commands of "Input tray select", "Output tray select", "Print engine mode set" and "Paper size set", if the command with the argument is accompanied by another command with an argument. If neither the "feed start" command nor the "print start" command follows before, the previous command is erased from the command buffer and becomes ineffective.

This means that if no 'FF' or 'VT' command follows, the tray, paper size or mode specified by the command will be the selected tray, selected paper size or selected mode. It does not mean

These commands are not valid for the previous “feed start” command or “print start” command.

The print engine sets the mode or status specified by the "input tray select", "output tray select", "print engine mode select", or "paper size set" command, and then uses these commands. Hold until status or mode is reselected.

The print engine never clears the contents of the command queue by itself, but clears it with a command received from the controller. Also, the 'FF' and 'VT' commands in the command buffer are erased at the start of their execution.

If the mode set and tray select are done properly and a sufficient number of 'FF' and 'VT' commands are stored in the command buffer, or 'FF' and 'VT' commands are appropriated by the controller. When issued at time intervals, the print engine executes these commands at maximum throughput (print speed).

A general command transmission sequence for the controller to request the print engine to execute printing is shown below.

1) Input tray selection An input tray including a double-sided input unit is selected. If the argument is omitted, the previous tray is valid.

The previous tray is also effective when the "input tray select" command is not issued.

2) Output tray selection An output tray including a duplex output unit is selected. If the argument is omitted, the previous tray is valid.

The previous tray is also effective when the "output tray select" command is not issued.

3) Feed request Send a "feed start" command. If this command has not been issued, the next "print start" command is valid for feed and print.

4) Print request Send a "print start" command.

If the “/ PRINT signal ignore flag” of “system current mode” is “0”, the controller also
It is also possible to request the print engine to execute printing with the "print request sequence hand-shake between NT and / PREADY". Note that "/" before each signal means negative logic (low active).

This request is executed prior to the 'FF' and 'VT' commands. However, it is not stacked in the command queue. The print request sequence is valid only in real-time execution.

If the controller does not request printing with the / PRINT signal, the print engine mode is set to “ignore / PRINT signal” by issuing the 'DC4' command.
Mode should be set.

If the print engine receives the / PRINT signal and 'FF' and 'V
If a print request is received by both the T 'command and the command timing and sequence, a serious error may occur in the execution of the command.

The controller queries the print engine's current status (eg, the currently active input tray) just prior to requesting the print engine to perform printing via the / PRINT signal line.

A response to a command (command marked with *) stored in the command buffer is transmitted from the print engine immediately after receiving the command, not when the command is executed.

As such, the content of the response may sometimes differ from the actual status of the execution of the command. For example, after responding to the “Input Tray Select” command, if a cassette of a different size is mounted on the selected input tray, the actual paper size will be “Input Select”.
This is different from the size sent by the print engine in response to the command.

In such a case, the status of the print engine becomes an error state (input size mismatch).

For the "Status Request" command, which queries the currently active input tray, the currently active output tray, and the current mode status of the system, the print engine issues the "FF" command immediately after the start of execution or the second command. Answer the currently active tray specified for the mode 'VT' command, or answer the currently active mode at that time.

The print engine will not respond to the tray code or mode specified by a command that has not been executed in the command queue.

The capacity of the command buffer should be as large as possible, depending on the maximum print speed of the print engine, but if the print speed of the print engine is less than 20 pages / minute, it will be equivalent to 32 papers Having enough capacity is enough.

If the controller wants to change the currently active input or output tray because the paper is empty or full while the print engine is executing a 'FF' or 'VT' command. The controller first issues a "command buffer clear" command and then reselects a new input or output tray.

In some cases, the print engine must predict the status of each unit and predict a response in response to the predicted status.

For example, a screen unit overflow or empty paper status indicates that the previous command was still in the command buffer and has not yet been executed.
Predicted to depend on previous commands.

By the way, as described above, the controller 2 receives the "paper feed link tray mode" and the "paper output link tray mode" by the command of the controller 2 from the host system 1 or the mode setting from the operation panel 25 shown in FIG. Is set, the controller 2 issues a 'DC4' command to the print engine 3 with the bits b2 to b0 of the argument set to "010".

In response to the 'DC4' command, the printer engine 3 is set to the "do not restart automatically after error is cleared" mode.

When this mode is set, the controller prohibits the print engine from automatically resuming operation after the error is cleared.

If an error occurs in the print engine in this mode, the execution is not automatically started when the error is cleared, even if there are still unexecuted 'FF' or 'VT' commands. .

Then, the print engine waits for reset of the “restart wait flag” by the reset command from the controller.

Since this is a function related to the gist of the present invention, a specific example thereof will be described later.

Communication between Print Engine and Option Next, communication between the print engine 3 and the option units 15 to 18 as various additional devices will be described.

The communication conditions between the print engine and the option unit are the same as the communication conditions between the controller and the print engine described above.

1. Interface: Asynchronous serial I / F 2. Communication speed: 9600 baud 3. Parity bits: None 4. Stop bit: 1 The communication protocol was briefly described earlier in the description of the basic system configuration. I will explain this in more detail.

Also in this case, communication from the print engine to the option unit is performed by transmitting a command, and communication from the option unit to the print engine is performed by transmitting a response.

An example of the format of this command and response is shown in FIG.

One command is by connexion configured operator and Agiyumento, b ₇ ~b ₅ argument is always "111", also shows logical ID code option Chillon Units - To communicate the operator b ₇ ~b ₅ print engine .

The operator also serves as the end of one instruction.

The types of commands used in this embodiment are as follows.

<Basic command> 1. Inquiry unit status (Inquire unit status) “*** 10001” 2. Inquire paper size “*** 10010” 3. Inquiry unit condition (Inquire unit condition) “*** 10011” 4.Inquire unit availability “*** 10100” 5.Inquire unit specification #
1 (Inquire unit specification # 1) “*** 1010
1 "6. Inquiry Unit Specification #
2 (Inquire unit specification # 2) “*** 1011
0 "7. Inquiry Unit Specification #
3 (Inquire unit specification # 3) “*** 1011
1 "8. Inquiry exited paper ID" *** 11000 "9. Inquiry unit firmware version" Inquire unit firmware version "" *** 11111 "10. Tray selection" *** 00001 "11. Mode setting (*** 00010) 12. Paper size setting (*** 00011) 13. Paper feed start (*** 00100) 14. Paper feed stop “*** 00101” 15. Paper feed restart “*** 00110” 16. Paper eject start “*** 01000” 17. Paper eject end “**** 01001” 18. Initializing “**** 01110” 19. Abort “** 01111” 20. Print engine path length (Length of print engin path) “*** 01010” 21. Registration distance (*** 01011) 22. Transport velocity “*** 01100” <Enhancement command> 23. Assign device ID (Assign Device ID) "*** 11001" 24. Inquire assigned Device ID "*** 11010" 25. Inquire device ID (Inquire Device ID) "*** 11011" These commands Is always performed in real time by the option unit.

Each option unit has a specific tray selection, mode set, paper size set, print engine
Path length, resist distance, transfer speed, and specified device ID
Mode, status, or designation is retained until re-selected by these commands.

Commands must be sent to the operator first with arguments, but the arguments of the command consisting of arguments and operators can be omitted, and the option unit must correctly recognize commands without arguments.

For example, if the print engine sends a command without arguments, such as an "inquire unit status" command, such as the "inquire unit status" command, the argument before the same command to the same logical ID unit is valid as the effective argument. is there.

However, the “paper eject start” command,
The “assign device ID” command shown in FIG. 13 (b) and the “inquire device I” shown in FIG. 13 (d)
Except for the D "command. In these commands, the previous argument is never valid.

Also, arguments for other commands and other logical
Arguments to ID units are invalid in any case.

If there is no valid argument on the option unit side when the command is received, the option unit must take the default value as the effective argument.

The response is a message sent from the option unit to the print engine, and indicates that the command has been received. All of the response is the length of one byte, b ₇ is summer to "0".

If the option unit does not support the function of the received command, the option unit must return <7Fhex>, that is, "01111111" as a response.

FIG. 13B shows an “assign device ID” command transmitted when the print engine assigns a device ID to a logical ID, and a format of a response transmitted from the option unit receiving the command.

This b ₃ ~b ₀ arguments command enters the device ID code is assigned, the operator of b ₇ ~b
₅ (indicated by ***) contains the logical ID code to be assigned.

For example, if this command is “111 × 0010,00011001”, “device ID“ 0010 ”(INP # 3: mass paper feeding unit 17, corresponding to mass paper feeding device 5B in FIG. 3) is assigned a logical ID.
Assign it as "000" (IN # 1). "

In response to this, the CPU of the option unit with the device ID “0010” (the large-volume sheet feeding unit 17 in the above example) recognizes this and returns a response of “00000010”.

This means that “device ID“ 0010 ”is changed to logical ID“ 000 ”(IN
# 1). "

Here, no Units - type code to the device ID code, two bits of b _6, b ₅ logical ID code is Units - type coating, determination since in this example, "00" represents the Imp bracts Units - it can.

FIG. 13 (c) shows a command for inquiring the device ID of an option unit assigned to a specific logical ID.
D "command and its response. This command is an operator-only command without any argument. For example," 00011010 "inquires each option unit about what is assigned to the logical ID" 000 ". Will do.

If the option unit having the assigned device ID is a large-volume feeder, a response of “00000010” (input option unit “0010” is assigned to the logical ID IN # 1) is then sent. Will return.

FIG. 13 (d) shows an "inquire device ID" command for inquiring whether or not a specific option unit can communicate, and a response thereto.

The ID code of the device to query the b ₃ ~b ₀ argument to this command, add Units - Type code to b _7, b ₆ operators. For example, “111 × 0010,00 × 1101
"1" is a command for inquiring whether the input option unit "0010" (mass feed unit 17) can communicate.

If the large-volume sheet feeding unit 17 is assigned, a response of “000 × 0010” is returned.

As described above, the command operators b _{7 to} b ₅
Is the global ID address "110", it indicates that the command is a global ID command.

When a global ID command is transmitted from the print engine, all of the option units in a communicable state must execute the command according to this command as much as possible. However, the option unit does not issue a response to this command, and the print engine can issue the next command without waiting for a response.

Initial Setup Next, the initial setup of the laser printer system will be described with reference to FIGS. 14 and 15. FIG.

FIG. 14 shows the relationship between the transmission and reception of signals between the operation panel, the host system, the controller, the print engine, and each of the option units at the time of initialization, and FIG. 15 is a flowchart showing the operation of the print engine.

Referring mainly to FIG. 15, when the power is turned on (power is turned on) and when an initialization command is received from the controller, the print engine sends the initialization command to all the additional devices (option units).

This initialization command may be a global ID command.

Then, the print engine itself performs initialization and self-diagnosis to perform initialization, and all communicable additional devices that have received the initialization command also perform initialization and self-diagnosis to initialize.

Thereafter, it is determined whether or not this printer system is an enhanced system. If YES, the device is an enhanced system. Therefore, the communication enable / disable state of all device IDs (48 IDs) is checked twice or more, and each device ID is checked. When the state becomes the same as the previous cycle, the state of each device ID is determined.

The reason why the results of the two confirmations are coincident is to prevent the state of the additional device in an unstable state such as a transient state when the power is turned on or off from being erroneously determined.

Next, one device ID is assigned to one logical ID in priority order, and a system configuration is established.

 Here, the priorities include the following 1 and 2.

Priority 1: Communication active device Priority 2: Younger device ID code On the other hand, if it is not an enhanced system, it is a basic system, so all logical ID units (5 IDs)
Is confirmed twice or more, and when the state of each logical ID unit becomes the same as the previous cycle, the state of each additional device is determined, and the system configuration is established.

The print engine must not issue any command to any option unit during initialization of the print engine itself.

Also, while any option unit is initializing itself, it must not send any response to the print engine.

After establishing the system configuration,
The print engine can communicate with the controller, but until then, the / PEDTR signal, which is a communication ready signal with the controller, must be turned off.

Engine and Option Status Confirmation FIGS. 16 to 18 show a detailed flow of communication for the controller 2 to confirm the status (status) information of the print engine 3 and a specific option unit.

FIG. 19 shows the print engine status code responded by the print engine and its contents.
The options and responses to which the option unit responds are shown in the figure.
It shows the input / output unit status code and its contents.

The outline of communication between the controller, the print engine, and the option unit will be described with reference to these drawings.

First, as shown in FIG. 16, a "printer general status" code (a code for asking the general condition of the printer) is sent from the controller to the engine. Bit b _{0 of} this command
Bb ₆ = 0 indicates a request for a general status.

Engine contrast, returns the response, shows the overview of the b ₀ ~b of each bit of the ₆ "1" or "0" each of printer status.

Next, the controller sends a "print engine status" command to the engine for asking the status of the engine unit.

If bit b ₆ is "0" for this command, the engine to the controller, priority is shown in top priority (FIG. 19 among the states of the engine unit that currently exist "print engine status code" 1 → 64) is response information positioned at the highest top level, if there is no information to be returned if the bit b ₆ of the response to "1", bit b ₅ ~b ₀ sends a response remains undefined.

Controller if bit b ₆ is "1" in the response, then stop the question the status to the engine at that time, moves to query status of the next Yunitsuto. If the bit b ₆ is "0" in response, because still known state information to be is present in the status punishment Hua of the engine and sends the code to ask the status of the engine again.

At this time, since the bit b ₆ of the command is not the highest priority information again to "1" is sent, the bit b ₆ to ask the state information of the next priority was last response to "1",
A command of "print engine status" is transmitted, and the status information of the next priority is obtained by a response from the engine.

The controller must keep asking until bit _{6 of} the response becomes "1". Thus, the controller can know all the current engine states.

The status code returned by the response is
As shown in FIG. 19, a table is negotiated between the engine and the controller.

After the status inquiry to the engine is completed, as shown in FIG. 17, the controller proceeds to the engine to inquire the status of each additional device (option unit).

As for the inquiry command “input unit # 1 status”, bits b _{5 to} b ₀ are “001001”.

Upon receiving this, the print engine sends an "ink unit status" command to the input unit # 1, and receives a response from the input unit # 1.

Exchange of presence information therebetween state also, controller and so exchange between the engine has a bit (b ₄₎ indicating whether or not ask the information in the following priority command side querying, answering side the response Has a bit (b ₆ ) indicating whether the status buffer for storing the status is empty or not, and until the status buffer is found to be empty, the controller enters the input unit # into the engine.
Inquire about the status of 1.

The status code returned in the response is
As shown in FIG. 20, a table is established between the engine, the controller and the option.

The engine is thus input unit # 1
The state information obtained from is transmitted to the controller by a respence.

In the same manner, the controller passes through the engine,
The status of the input unit # 2, output unit # 1, output unit # 2, and double-sided unit is sequentially inquired.

Next, the details of the “printer general status” command and the response thereto will be described.

This command is used when the argument is 80 in hex code.
_H, since (in hex code 05 _H) operator 'ENQ' is represented as 80 _H 'ENQ', status request
One of the commands inquires about the general status of the engine system including the option unit.

Each bit of the response indicating the status from the print engine to this command is as follows.

Response _{(status): b 7: "0"} b 6: There paper in paper path system b _5: discharge ID to the discharge ID in the buffer there b _4: Pepajiyamu Fixed b _3: print start the ready (resist point the ready) b ₂ : Feeding start (during feeding) b ₁ : Status group code 1 b ₀ : Status group code 0 (Description) 1. “There is paper in the paper path of the system” Any of the input trays (excluding double-sided units)
When there is any paper in the engine system paper path including the double-sided path, the paper supply of which has been started and the output of which has not been completed in any of the output trays (excluding the double-sided unit). The flag is set to "1".

If there is no paper in the paper path of the engine system, this flag is set to "0".

2. The flag of "paper discharge ID exists in paper discharge ID buffer" is set to "1" when one sheet of paper has been discharged to an output tray other than the duplex unit. This flag is set to "0" when the discharge ID buffer becomes empty due to the issuance of the event report # 3 or the issuance of a response to the 'ACK' command.

If the paper ejection ID still remains in the paper ejection ID buffer, this flag remains "1", indicating that the paper ejection ID buffer is not empty.

The controller issues the "Inquire Exit Paper ID" or "ACK" command to
You can ask for the paper ejection ID.

3. "Paper jam fixation" In some cases, even if a jam (paper jam) occurs in the engine system during printing, paper other than the jammed paper may be transported and discharged to the output tray.

Then, the jammed paper is fixed (fixed) when the discharge of the other paper is completed. The engine sets this flag to "1" when the jammed paper is fixed.

When this flag is "1", the controller can ask the ID number of the jam paper by issuing a status request command.

The engine sets this flag to "0" when it is confirmed that no paper remains in the paper path after the jam recovery operation is performed.

4. "Print start ready" This flag is set to "1" when the fed paper is ready to be printed at the registration position.
This flag is set to "0" when no paper is waiting for printing at the registration position.

When this flag is "1", the engine starts printing to execute the 'VT' command.

The controller may send a print start command without waiting for this flag, depending on the correct print sequence.

5. "Feed start (during feeding)" This flag is set to "1" when the engine starts feeding one sheet of paper.

This flag is set to "0" when the engine can start feeding the next paper from the currently used input tray. The timing of setting this flag to "0" depends on what tray is to be used next.

6. "Status group code" This 2-bit flag indicates the general status of all engine systems.

 The meanings of these flags are as shown in FIG.

The status indicated with this status group code depends on the event report enabled state. This means that the status group code changes according to the bits b ₁ and b ₀ of the argument of the 'ETB' command which is the command of “event report enable”.

FIG. 22 shows the relationship between the bits b ₁ and b ₀ and the contents of the general status indicated with the status group code.

Restarting after resetting the error As described above, “paper feed link tray mode”, “paper output link tray mode”, “jam back up mode”
The following operation will be described below in the case where any one of the modes is set in the controller 2 and the controller 2 sets the "do not start automatically after error release" mode for the print engine 3 by the "DC4" command. .

In this mode, if any error (errors of priority 40 to 17 shown in FIG. 19) occurs in either the print engine 3 or the option units 15 to 18 in the image forming system, the print engine 3 starts printing. The corresponding status flag in the system and printer engine status codes is turned on, and the "restart wait flag" of priority order 42 is turned on.

Further, the print engine 3 sends a message called an event report to the controller 2 to notify occurrence of an error.

Of course, the print engine 3 stops entering the next image forming step (stops executing the command in the command buffer).

The controller 2, which has been notified of the occurrence of the error by the event report from the print engine 3, prompts the operator to execute an error recovery operation through the operation panel 25, and informs the host system 1 that the error has occurred.

In the link tray mode, the print engine 3 prepares for switching of the paper feed tray or the discharge tray, and in the jam backup mode, prepares for image backup (re-opening).

Further, the bit b ₂ ~b ₀ of Agiyumento from the controller 2 "010" by the the 'CAN' command in connexion, clear all the contents of the command cue punishment Hua of the print engine 3.

In any case, the print engine 3 does not start on its own even if the error is recovered, so that the timing for clearing the command queue may be provided later.

In the case of the link tray mode, as soon as the controller 2 is ready, the controller 2 issues a paper feed tray or a paper feed tray switching command to change the active tray.

As a result of this change, the status flag indicating "no paper" or "full paper" for the active tray of the print engine 3 is turned off.

As a result, only the “restart wait flag” is turned ON.

Before the controller 2 clears the command buffer as described above and then issues a command to switch the paper feed tray and / or the paper discharge tray, the operator supplies paper to the paper feed tray. Alternatively, even if the work of removing the paper from the discharge tray is performed, the print engine 3 does not resume the execution of the instruction as long as the “restart wait flag” is ON.

When the paper feed tray and / or switching of the discharge tray is performed, the controller 2'll immediately bit b ₂ ~b ₀ of Agiyumento to "101" and the 'CAN' command connexion Clear "restart wait flag" I do.

As a result, the image forming process of the image forming system is restarted, and normal printing is performed.

In the case of the jam backup mode, the operator, who has been notified of the occurrence of the error by the display of the host system 1 or the operation panel 25, performs a predetermined error repairing operation such as removing the jammed paper, thereby performing a print engine operation. 3
"Paper jam status flag" turns off.

Then, as soon as the backup image is ready, the controller 2 operates the print engine 3 in the same manner as described above.
The "restart wait flag" is turned off to restart image formation. As a result, normal printing is resumed.

Note that if the link tray mode and changer Muba stick mode is canceled, the controller 2 by the the 'CAN' command to "101" to bit b ₂ ~b ₀ of Agiyumento connexion,
It is sufficient to clear the "restart waiting flag" and release the "do not start automatically after error is released" mode.

Then, the procedure of communication between the controller 2 and the print engine relating to the processing after the error recovery is simplified, and the overhead of each other is reduced.

Therefore, it is possible to prevent a problem that an image is lost or a page is missing after the error is canceled in the paper feed link tray mode. Further, in the paper discharge link tray mode, it is possible to prevent a problem at the time of overflow detection due to paper curl and a malfunction in the jam backup mode.

The present invention can also be applied to a laser printer system in which a controller (image processing unit) is built in a host system and connected to an engine (image forming unit) by LPVI.

Further, the present invention is not limited to a laser printer system,
The present invention is also applicable to an image forming system using another page printer, a digital copying machine, a facsimile machine, or the like.

〔The invention's effect〕

According to the present invention, an image processing section (controller), an image forming section (print engine), and various additional devices are provided, and various commands relating to image formation are sent from the image processing section to the image forming section. In an image forming system in which the image forming unit stores specific commands among the various commands in its own buffer and sequentially executes these specific commands to form an image, an error is generated in the image forming unit or the additional device. Occurs, the image forming apparatus interrupts the execution of the instruction stored in the buffer, and does not automatically restart the image forming operation even if the error is cleared, and receives a restart instruction from the image processing unit. Then, the execution of the command is restarted to restart the image forming operation.

As a result, it is possible to prevent a problem that image loss or page missing occurs in the link tray mode, for example. In addition, it is possible to prevent a problem at the time of detecting an overflow due to the curl of the discharged sheet and a malfunction in the jam-backup mode. Therefore, the reliability of the image forming system is significantly improved.

Also, when a specific operation mode such as the link tray mode or the jam backup mode is not set, the image processing unit sets the image forming unit to restart the execution of the above command immediately after the error is cleared. By doing so, the procedure of communication between the image processing unit and the image forming unit relating to the processing after error recovery can be simplified, and the interruption time of image formation can be shortened.

Further, when operating in the jam backup mode, the image processing unit transmits a command to clear the command stored in the buffer F to the image forming unit before transmitting the restart command. By clearing the previously transmitted command relating to image formation and transmitting a print command relating to the next recording sheet again, occurrence of image omission can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an image forming system according to the present invention, FIG. 2A is a block diagram showing a system configuration of an embodiment of the present invention, and FIG. FIG. 3 is an explanatory diagram showing a configuration example of a command issued to an apparatus, FIG. 3 is a block diagram showing a system configuration of another embodiment of the present invention, and FIG. 4 is a laser printer system as one embodiment of the present invention. FIG. 5 is a block diagram showing the configuration of the controller 2 in FIG. 4, and FIG. 6 is a block diagram showing the data processing flow and the RAM 22 in FIG.
FIG. 7 is a block diagram showing a relationship between each buffer and a file, FIG. 7 is an external view showing a specific example of the operation panel 25 in FIG. 5, FIG. 8 is an explanatory diagram of each signal of LPVI in this embodiment, FIG. 9 is an explanatory diagram showing the relationship between the printing area and the image signal in this embodiment. FIG. 10 is a schematic diagram of an engine main body and various optional units connected to the engine body constituting the printer system. Is a block diagram showing the configuration of the engine control unit, FIG. 12 is an explanatory diagram of commands and responses used between the controller and the print engine, and FIG. 13 is a command used for communication between the print engine and each option unit. FIG. 14 is a flowchart showing the operation of the entire system at the time of power-on and at the time of execution of initialization in this embodiment. FIG. 16 is a flow chart showing the operation of the print engine at that time. FIGS. 16 to 18 are flow charts showing the exchange of commands and responses when the state of the print engine and the option unit is confirmed by the controller. And FIG. 20 is an explanatory diagram showing a table of a print engine, a status code, an option unit, and a status code which are also used for the communication, and FIG. 21 is an explanatory diagram showing a relationship between a status group code and a status level represented thereby. FIG. 22, FIG. 22 shows the bit b ₁ of the argument of the 'ETB' command,
b ₀ and explanatory view showing the relationship between the content such as the di-energy Lal status, shown with a status group code, FIG. 23 through FIG. 27 is an explanatory diagram for explaining a conventional art and its problems, respectively. DESCRIPTION OF SYMBOLS 1 ... Host system 2 ... Controller (image processing part) 3 ... Print engine (image forming part) 4 ... Image forming apparatus (printer) main body 5, 5A-5G ... Various additional apparatuses 10 ... Engine main body 13 ...... Reversing unit (reversing paper ejection device) 15 ... Mail box (multi-stage paper ejection device) 16 ... Double-sided unit (double-sided conveyance device) 17 ... Mass feeding unit (mass feeding unit) 18 ... Mass ejection Paper unit (mass discharge device) 19 Printer table 20 Controller CPU 25 Operation panel 27 Option interface 29 Engine interface 30 Engine control unit (engine driver) 31 Engine control unit CPU 33 RAM of the engine control unit (including the command key buffer)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 29/38 G06F 3/12

Claims (3)

(57) [Claims] An image processing section for receiving character information or image information from a host system to generate image image information; and an image forming section for receiving image image information from the image processing section and forming an image on a recording medium. The image processing unit comprises various additional devices that are detachable from the image forming unit and feed, convey, or discharge the recording medium. The image processing unit sends various instructions related to image formation to the image forming unit. The image forming unit sends out the specific commands among the various commands in a buffer in the image forming unit and sequentially executes the specific commands to form an image. When an error occurs in the image forming unit itself or the various additional devices, execution of the instruction stored in the buffer is interrupted, and after the error is released, the image processing is stopped. An image forming system provided with means for restarting the execution of the command by receiving a restart command from the unit. 2. The image processing section according to claim 1, wherein said image forming section sets said image forming section so that, when a specific operation mode is not set, said image forming section restarts execution of said command immediately after error cancellation. The image forming system according to claim 1, further comprising: 3. The image processing unit according to claim 2, further comprising means for transmitting a command to clear the command stored in the buffer to the image forming unit before transmitting the restart command. Item 2. The image forming system according to Item 1.