JPH1058800A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the consumption of recording papers in debugging compared with conventional devices heretofore available while making the debugging for an image forming device effective in the same manner as the conventional devices. SOLUTION: In an image forming device 1 connected with a host device 4 and executing the image forming operation based on commands transmitted from the host device 4, an interpretion statement storage means 7 for storing interpretation statements to be used for the interpretation of the commands and a control means 2 for reading the interpretation statements corresponding to the commands transmitted from the host device 4 out of an interpretation statement storage means 7 and transmitting the interpretation statements thus read out to the host device 4 are provided. Also the command error history is transmitted to the host device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile, and the like.
The present invention relates to an image forming apparatus that is connected to a higher-level device and executes image formation based on a command sent from the higher-level device.

[0002]

2. Description of the Related Art Conventionally, there has been known an image forming apparatus which is connected to a host device and executes image formation based on a command from the host device. The image forming apparatus analyzes a command sent from a higher-level device using an emulation program as an analyzing unit, and executes an image forming operation based on the analysis result. Therefore,
When adjusting the image forming apparatus before shipping the image forming apparatus from the factory, for example, check whether the image forming apparatus executes a faithful image forming operation based on a command from a higher-level apparatus, and if so, execute the operation faithfully. In such a case, a so-called debugging work for correcting the emulation program or the like is required. Conventionally, regarding this debugging work, after a person checks a command transmitted from a higher-level device, a person interprets the meaning of the command, that is, what kind of image forming operation is performed by the command. Thus, by checking the image formed on the recording paper based on the command, it has been investigated whether or not the image formation according to the command has been performed. However, in the above-mentioned conventional debugging work, since a person had to check the meaning of the command each time, much time and labor were required. In view of such a point, a storage unit for storing a command interpretation sentence is provided in the image forming apparatus, and an apparatus that reads out the interpretation sentence corresponding to the command input to the image forming apparatus from the storage unit and forms an image on recording paper is provided. It has been proposed (Japanese Patent Laid-Open No. Hei 6-321560). According to this image forming apparatus, the command corresponding to the command sent from the higher-level device and the command interpretation statement are image-formed on the recording paper and output, so that it is easy to understand (interpret) the meaning and meaning of the command. Debugging work can be performed efficiently.

[0003]

However, according to the prior art described in the above-mentioned Japanese Patent Application Laid-Open No. Hei 6-321560, since the command interpretation statement is formed on the recording paper, the recording paper is inevitably consumed. become. In particular, when a large number of commands are sent from the higher-level device to the image forming apparatus,
The amount of recording paper required to form an image of the command interpretation statement also becomes large, and an undesirable situation arises from the viewpoint of resource saving.

The present invention has been made in view of the above problems, and has as its object to improve the efficiency of debugging work of an image forming apparatus in the same manner as the above-described conventional apparatus.
An object of the present invention is to provide an image forming apparatus capable of reducing the consumption of recording paper in a debugging operation as compared with a conventional apparatus.

[0005]

According to a first aspect of the present invention, an image forming apparatus is connected to a higher-level device and executes an image forming operation based on a command sent from the higher-level device. In the image forming apparatus, an interpreted sentence storing means for storing an interpreted sentence used for interpreting the command, and the interpreted sentence corresponding to the command sent from the higher-level device are read from the interpreted sentence storing means and read out. Control means for transmitting the interpreted sentence to the host device.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the transmission of the interpreted sentence to a higher-level device is completed by completing image formation based on the command sent from the higher-level device. This operation is performed after a subsequent recording sheet is discharged from the image forming apparatus.

According to a third aspect of the present invention, in the image forming apparatus of the first aspect, the command analyzed after a lapse of a predetermined time from completion of analysis of a series of commands sent from the higher-level device to the image forming apparatus. Is transmitted to the image forming apparatus.

According to a fourth aspect of the present invention, in the image forming apparatus of the first aspect, each time the analysis of each command from the higher-level device is completed, the interpretation sentence of the command is sequentially transmitted to the higher-level device. It is assumed that.

In the image forming apparatus of the first, second, third, or fourth aspect, an interpretation sentence corresponding to a command sent from the higher-level device is transmitted to the higher-level device, and the interpretation sentence is displayed on the higher-level device. The command interpretation statement is not formed on the recording paper. This makes command interpretation as easy as conventional devices,
Recording paper for forming an image of the interpretation is not required.

In the image forming apparatus according to the second aspect of the present invention, the command interpretation sentence is transmitted to the host apparatus, and the image forming on the recording sheet based on the command is completed, and the recording sheet is discharged from the image forming apparatus. In the image forming apparatus according to the third aspect, the analysis is performed after a lapse of a predetermined time from the point in time when the analysis of the entire sent command is completed. Perform each time it occurs.

If the image formed based on the command sent from the host device is different from the image originally formed by the sent command, analysis of the command due to a bug in the emulation program may be a factor. It is conceivable that there is a mistake and that the command sent from the higher-level device is a command that cannot be originally analyzed by the emulation program. In order to make the debugging work more efficient, it is necessary to analyze which factor caused the situation where an image different from the original image to be formed was caused.

According to a fifth aspect of the present invention, in the image forming apparatus of the first, second, third, or fourth aspect, when an abnormal command is sent from a higher-level device, the history of the command is stored in a command error history. When the command interpretation statement is transmitted to a higher-level device, the stored command error history is transmitted to a higher-level device. This makes it easy to analyze the cause of an image formed based on a command from a higher-level device when the image is different from the originally intended one.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a laser printer as an image forming apparatus will be described below. FIG. 1 is a laser printer according to the present embodiment (hereinafter referred to as a laser printer)
Simply called "printer". FIG.

The printer 1 according to the present embodiment is connected to a host device 4 as a host device such as a computer or a word processor, and forms an image on a recording sheet based on a command sent from the host device 4. Is possible. In order to perform such image formation, the printer 1 has the following configuration. That is, the printer 1 is broadly composed of a printer controller (hereinafter abbreviated as a controller) 2 which is a control means for controlling the entire printer, and a printer engine 3 (hereinafter referred to as an image forming means) which actually forms an image on a recording sheet. , The engine is abbreviated), and instructions such as various mode settings from the user are given to the controller
The operation panel 13 displays various states of the printer 1.

The controller 2 includes a CPU (Central Processing Unit) 10, a RAM 5, a font ROM 6, a program ROM 7, a nonvolatile RAM 8, an IC card 9, an engine interface 11, a panel interface 12,
It comprises a host interface 14 and these are connected by a system bus 15.

The CPU 10 is a control device, and based on a signal from the operation panel 13 or the host device 4,
By executing a predetermined program, various controls performed in the printer controller 2 are executed. The above CP
A program used for control by U10 is stored in a program ROM 7 which is a read-only memory. The ROM 7 also functions as an interpreted sentence storage unit that stores an interpreted sentence indicating the content of each command from the host device, and also stores data indicating the content of the command error, which will be described later.

As described above, in addition to the program ROM 7, the controller 2 stores the font R
A memory such as the OM 6, the RAM 5, and the nonvolatile RAM 8 is provided. The font ROM 6 is a read-only memory, like the program ROM 7, and stores pattern data of various fonts such as characters used for image formation. On the other hand, the RAM 5 and the nonvolatile RA
M8 is a random access memory that enables both writing and reading of data.

The RAM 5 is used as a working memory when the CPU 10 executes various controls. Further, the RAM 5 includes a reception buffer for temporarily storing a command sent from the host device 4,
When bitmap image data is created based on the above command, it is used as a frame buffer for storing this. Further, the RAM 5
It is also used to store the interpretation sentence corresponding to the analyzed command and to store the command error history. This will be described later.

The nonvolatile RAM 8 is a battery backup memory capable of retaining stored data even when the power is turned off. The nonvolatile RAM 8 stores the contents of mode instructions from the operation panel 13, environment setting data of the printer 1, and the like.

An interface is required for the controller 2 to communicate with a device provided outside the controller 2. For this purpose, the controller 2 is provided with an engine interface 11, a panel interface 12, a disk interface 1
3 and a host interface 14.

The engine interface 11 is an interface for communicating commands, statuses, image data, and the like between the controller 2 and the engine 3. Panel interface 1 above
2 is between the controller 2 and the operation panel 15;
This is an interface for communicating commands and status. The disk interface 13
This is an interface for performing communication between the controller 2 and the disk device 16. The host interface 14 is an interface for the controller 2 to perform bidirectional communication with the host device 4. Through the host interface 14, the controller 2 transmits information to the host device, and receives information including commands and the like from the host device 4.

In the printer 1 having the above configuration,
A general operation from when a command is sent from the host device 4 to when an image forming operation based on the command is performed is as follows. The command from the host device 4 is received via the host interface 14 and is temporarily stored in a reception buffer formed on the RAM 5. The commands include control codes and character codes necessary for image formation.

When the storage of the command in the reception buffer is completed, a CPU interrupt is generated, and the CPU 10 is notified that the command has been received. The CPU 10 that has received the notification retrieves the command from the reception buffer and performs analysis according to the emulation program stored in the program ROM 7.
As a result of this analysis, each command is converted into an intermediate code called a display list.

The intermediate code is stored in a page buffer formed on the RAM 5. Thus, when the storage of the intermediate code for one page is completed in the page buffer, C
The PU 10 executes the system program stored in the program ROM 7 and stores the intermediate code in the RAM 5
The image data is developed as bitmap image data in the frame buffer formed above. When the development is completed, the controller 2 sends a paper feed unit selection command and an image formation command to the engine 3 via the engine interface 11, and sends the image data developed in the frame buffer. Engine 3 receiving the above-mentioned paper feed unit selection command and image forming command
Executes the paper feed specified by the paper feed selection command, and forms an image based on the image data.

The image forming operation of the engine 3 will be described with reference to FIG. FIG. 2 is an explanatory diagram for explaining the operation of the engine 3. The image data from the controller 2 is input to the optical writing unit 22.
The optical writing unit 22 is provided with a laser diode (not shown) that blinks based on the image data and generates a light beam. The light beam from the laser diode is deflected by a polygon mirror 22a rotating at a high speed, and is deflected by an optical system 22 such as an fθ lens.
The light is uniformly charged by the charging device 27 via the mirror b and the mirror 22c, and is guided to the photosensitive member 23 that rotates clockwise in the drawing. Then, the light beam forms a latent image corresponding to the image data on the surface of the photoconductor 23. This latent image is
The toner image is visualized by the toner development by the developing device 24 and becomes a toner image.

On the other hand, while setting the timing of the formation of the latent image and the formation of the toner image, the first paper feed unit 2 specified by the paper feed selection command from the controller 2.
0, or the recording paper is fed from either the second paper feeding unit 21. The recording sheet is once again stopped by abutting the leading end of the recording sheet on the pair of registration rollers 26 in the conveying direction, and then reconveyed at a timing corresponding to the toner image on the surface of the photoconductor 23. A transfer device 25 is provided at a position downstream of the registration roller pair 26 in the transport direction and facing the photoconductor 23, and the transfer device 25
3 is transferred to the recording paper. The recording paper on which the transfer has been completed is transported by the transport belt 29 to a fixing device 30 including a heating roller and a pressure roller, and the toner image on the recording paper is fixed on the recording paper. The recording paper on which the fixing has been completed is transported by the transport roller pair 31 and is discharged onto a paper discharge tray 32. After the transfer by the transfer device 25 is completed, the surface of the photoconductor 23 is cleaned by the cleaning device 28 to collect the residual toner. Thus, the image formation for one page of the recording paper is completed.

In the present embodiment, in order to facilitate the debugging operation of the printer 1 and reduce the consumption of recording paper during the debugging operation, an interpretation sentence of a command sent from the host device 4 to the printer 1 is transmitted to the host computer. The data is transmitted to the device 4. A first embodiment in the case where a command interpretation statement is transmitted to the host device 4 will be described with reference to the flowchart of FIG.

First, the controller 2 (specifically, the CP
U10) determines whether or not data exists in the reception buffer formed in the RAM 5, that is, whether or not a command has been received from the host device 4 (step 30).
1). If there is no data in the reception buffer, "other processing" such as command reception waiting in step 309
However, if data (command) exists in the reception buffer, a command analysis process in step 302 is performed. This command analysis processing is performed by the emulation program stored in the program ROM 7 as described above. When debugging the image forming apparatus, if the emulation program in the program ROM 7 has a bug, the bug is corrected so that the program can be rewritten.
It is convenient to use a PROM or EEPROM.

When the analysis of one command is completed, the process proceeds to an image forming process (step 303). The "image forming process" includes processes such as conversion of the above-mentioned command into an intermediate code, development of the intermediate code into image data, transmission of the image data to a printer engine, and the like. After the process of step 303, the controller 2 determines whether or not the current mode is the debug mode (step 304). The setting of the debug mode is performed by the key operation from the operation panel 15 described above, or
This is performed according to a command instruction from the host device 4. If the result of the determination is that the mode is the debug mode, a command interpretation statement corresponding to the command analyzed in step 302 is read from the command interpretation statement storage area and stored in the command interpretation statement storage area together with the command (step 305). ). The command storage area is
The command interpreted sentence storage area is formed on the program ROM 7, and is formed on the RAM 5. (Hereinafter, margin)

FIG. 4 shows an example in which a command and its interpreted sentence are stored in the command interpreted sentence storage area. As illustrated in FIG. 4, the command and its interpretation are each 1
It is stored in correspondence with one to one. Here, the command interpretation sentence means a sentence that allows the user to understand the meaning of each command. For example, "ESC CP 10
The command interpretation statement corresponding to “0, 200” is “SET curs
ol position to (100,200) point ", which indicates that the command has the meaning of" set the cursor to the coordinates (100, 200) ".

When the storage of the series of commands and the command interpretation sentence in the command interpretation sentence storage area is completed, the controller 2 completes the image formation on the recording paper corresponding to the command in the engine 3. It is determined whether or not the paper has been discharged (step 306). If the result of this determination is that the discharge of the recording paper has been completed, the command stored in the command interpretation statement storage area and the command interpretation statement are transmitted to the host device 4 via the host interface 14 (step 307). ). Then, the transmitted command and the command interpretation statement are sequentially deleted from the command storage area (step 308). Thus, the transmission of the command interpretation statement to the host device 4 is completed. The command interpretation sent to the host device 4 is
The information is displayed on a display, which is a display device provided on the host device.

Next, a second embodiment relating to the operation of transmitting the command interpretation statement to the host device 4 will be described with reference to the flowchart of FIG. The second embodiment is similar to the first embodiment.
The difference from the first embodiment is that, in the first embodiment, the transmission of the command interpretation statement to the host device 4 is performed by forming an image on a recording sheet based on the command received by the printer 1 and discharging the recording sheet. The second embodiment is different from the first embodiment in that a command interpretation statement can be transmitted to the host device 4 every time an analysis result of each command is generated.

In the flowchart of FIG. 5, steps 501 to 505 are the same as in the first embodiment. In the second embodiment, it is determined in step 505 in FIG. 5 whether the immediate response mode is set. If the result of this determination is that the immediate response mode has been set, the command and the command interpretation sentence stored in the command interpretation sentence storage area are rewritten each time a command interpretation result is generated for each command.
4 to the host device 4 (step 50).
7). Then, the command whose transmission has been completed and the command interpretation statement are deleted from the command storage area (step 50).
8). If it is determined in step 506 that the immediate response mode has not been set, step 50
At 9, the operation indicated by reference symbol A in FIG. 3 is performed. That is,
After the discharge of the recording paper is completed, a command interpretation statement is transmitted. The setting of the immediate response mode can be set by a key operation from the operation panel 15 or by transmitting a command from the host device 4 to the printer controller 2.

FIG. 6 shows the contents of the command storage area when the immediate response mode is set in the second embodiment. As shown, the immediate response mode is set. In this case, one command and one corresponding command interpretation statement are stored.

Next, a third embodiment relating to transmission of a command interpretation statement to the host device 4 will be described with reference to the flowchart of FIG. The third embodiment is different from the first embodiment in that the command interpretation statement is transmitted to the host device 4 after the recording paper is discharged, whereas in the third embodiment, the recording paper is transmitted in the third embodiment. Irrespective of the presence or absence of paper ejection, it is possible to transmit a command interpretation sentence to the host device 4 after a certain period of time has passed after the analysis of the command.

In FIG. 7, steps 701 to 708 are the same as those in the first embodiment described above, and a detailed description thereof will be omitted. The features of the third embodiment are steps 709 to 713, particularly step 711 in FIG. In step 709, it is determined whether or not the debug mode is set. If the debug mode is set, it is determined whether the parsed command and the corresponding command interpretation statement are stored in the command interpretation statement storage area. (Step 710). As a result of this determination, if the command and the command interpretation statement are stored, it is determined whether or not a predetermined time has elapsed since the analysis of the stored command is completed (step 711). And if a certain time has passed,
The command stored in the command storage area and the command interpretation statement are transmitted to the host device 4 (step 7).
12) The transmitted command and the command interpretation statement are deleted from the command storage area.

According to the third embodiment, for example, when a command sent from the host device 4 to the printer 1 does not include a "discharge command" for instructing discharge of recording paper. However, the command interpretation sentence can be automatically transmitted to the host device 4.

Next, a fourth embodiment will be described with reference to FIG. In the fourth embodiment, not only the command interpretation statement but also the command error history is transmitted to the host device 4 in the first embodiment described above with reference to FIG. In FIG. 8, steps 801 to 810 are the same as in the first embodiment.
Steps 811 to 813 are the features of the fourth embodiment. That is, in the fourth embodiment, the command interpretation statement is transmitted to the host device 4 and the data (command and command interpretation statement) in the command interpretation statement storage area to which the command has been transmitted is deleted (steps 809 and 8).
After 10), it is determined whether or not there is a command error history (step 811).

Here, the command error history and the like will be described with reference to FIG. FIG. 9A is a diagram showing the contents of the command interpreted sentence storage area when a command error has occurred, and FIG. 9B is a diagram showing the contents of the command error history storage area. When a command error occurs, that is, when the controller 2 receives an abnormal command from the host device 4, data indicating that there is a command error is stored in the command interpretation statement storage area in association with the abnormal command. You. In FIG. 9A,
The portions indicated by the reference numerals are portions where a command error has occurred, and “ESC ZZ” and “ESC LT 2, 4”
Is an abnormal command sent from the host device 4. “Commond error!” Is data indicating that a command error has occurred. When a command error occurs in this manner, the controller 2 reads data indicating the content of the command error from the command error content storage area of the program ROM 7 in accordance with the generated command error, and stores the data in the command error history storage area. Store. FIG. 9B shows the state of the command error history storage area in which the contents of the command errors corresponding to the two command errors in FIG. 9A are stored.

Returning to FIG. 8, the description will be continued. If it is determined in step 811 that there is data indicating the content of the command error in the command error history storage area, the controller 2 sets the data indicating the content of the command error stored in the command error history storage area. Is transmitted to the host device 4 (step 812), and the command error history storage area is cleared (step 813).

As described above, according to the fourth embodiment, not only the fact that there is a command error is transmitted to the host device 4 as part of the command interpretation statement, but also the command error history is recorded as a command error history. Is transmitted to the host device. Therefore, compared to the first embodiment and the like,
Debugging work can be made more efficient.
In particular, when the image formed on the recording paper is different from the originally intended image, is the cause due to a bug in the emulation program of the printer, or is there a problem with the command itself from the host device 4? Can be easily confirmed.

Next, a fifth embodiment will be described. Fifth
In this embodiment, not only the command interpretation statement but also the command error history is transmitted to the host device 4 in the second embodiment described with reference to FIG. The fifth embodiment is different from the fourth embodiment in that:
In the fourth embodiment, the command interpretation statement and the command history are collectively recorded after the recording paper is discharged,
In contrast, the fifth embodiment transmits a command interpretation statement and a command error history to the host device 4 each time the analysis of each command is completed.

The operation of the fifth embodiment is shown in the flowchart of FIG. The feature of the fifth embodiment is that step 100
1 or later. That is, in step 1008, it is determined whether or not the immediate response mode is set. If the mode is set, a command interpretation statement is transmitted to the host device every time a command analysis result is generated (step 1008). 10
09, step 1010). If a command error has occurred and data exists in the command error history storage area described in the fourth embodiment (step 1).
011), and also transmits data indicating the contents of the command error to the host device 4 every time a command analysis result is generated (steps 1012 and 1013).

As described above, the transmission to the host device 4 as illustrated in FIG. 10 is performed. FIG. 10 exemplifies transmission to the host device 4 when two command errors have occurred, and transmission is performed in the order of the reference numerals in the figure. The contents of the command interpretation statement and the command error are the same as in the fourth embodiment.

[0045]

According to the image forming apparatus of the present invention, the command sentence is not formed on the recording paper by the image forming apparatus, but the interpreted sentence is transmitted to the host device. It has an excellent effect that it is possible to reduce the consumption of recording paper at the time of debugging work compared to the conventional device, by eliminating the need for recording paper for forming an interpretation sentence while improving the work efficiency. .

In particular, according to the image forming apparatus of the second aspect,
The command interpretation statement is transmitted after the image formation on the recording paper based on the command sent from the host device is completed and the recording paper is ejected from the image forming apparatus. In this case, the recording paper has already been discharged, and this is an excellent effect that the relation between the command and the image can be immediately checked by using the recording paper.

According to the image forming apparatus of the present invention, the line command interpreted sentence is transmitted to the host device after a lapse of a predetermined time from the time when the analysis of the entire transmitted command is completed. Even if a command to instruct paper ejection is not transmitted from the host device,
This has an excellent effect that the command interpretation sentence can be reliably transmitted to the host device.

In particular, according to the image forming apparatus of the present invention, a command interpretation sentence is transmitted to a higher-level device each time an analysis result of one command is generated. Among them, there is an excellent effect that it is possible for the host device to know up to which part the analysis is progressing.

According to the image forming apparatus of the present invention, in addition to the command interpretation sentence, the command error history is transmitted to the higher-level device, so that the image formed based on the command from the higher-level device is transmitted. When the image is different from the image that should be formed by the command, the factor analysis becomes easier,
As compared with the image forming apparatus according to the first, second, third or fourth aspect, the present invention has an excellent effect that debugging work can be performed more efficiently.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a printer.

FIG. 2 is an explanatory diagram illustrating an image forming operation in an engine.

FIG. 3 is a flowchart showing an operation according to the first embodiment.

FIG. 4 is a view exemplifying the contents of a command interpretation sentence storage area in the first embodiment.

FIG. 5 is a flowchart showing an operation according to the second embodiment.

FIG. 6 is a view exemplifying the contents of a command interpretation statement storage area in the second embodiment.

FIG. 7 is a flowchart illustrating an operation according to a third embodiment.

FIG. 8 is a flowchart showing an operation according to a fourth embodiment.

FIG. 9A is a diagram exemplifying the contents of a command interpretation sentence storage area in the fourth embodiment, and FIG.
The figure which illustrated the content of the command error history storage area in the Example of FIG.

FIG. 10 is a flowchart illustrating an operation according to a fifth embodiment;

FIG. 11 is a diagram exemplifying a transmission order to a host device in a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Printer controller 3 Printer engine 4 Host device 5 RAM 6 Font ROM 7 Program ROM 8 Non-volatile RAM 9 IC card 10 CPU 11 Engine interface 12 Panel interface 13 Disk interface 14 Host interface 15 Operation panel 16 Disk device 17 System bus 20 First paper supply unit 21 Second paper supply unit 22 Optical writing device 23 Photoconductor 24 Developing device 25 Transfer device 26 Registration roller pair 27 Charging device 28 Cleaning device 29 Conveyor belt 30 Fixing device 31 Conveyor roller 32 Discharge tray

Claims (5)

[Claims] 1. An image forming apparatus connected to a higher-level device and executing an image forming operation based on a command sent from the higher-level device, wherein: an interpretation statement storage means for storing an interpretation statement used for interpreting the command; An image reading means for reading out the interpreted sentence corresponding to the command sent from the host device from the interpreted sentence storage means and transmitting the read interpreted sentence to the host device. Forming equipment. 2. The image forming apparatus according to claim 1, wherein the transmission of the interpretation sentence to the higher-level device is completed based on the command sent from the higher-level device, and the recording paper after the image formation is used for image formation. An image forming apparatus, which is performed after a sheet is discharged from the apparatus. 3. The image forming apparatus according to claim 1, wherein after a predetermined period of time has passed since the analysis of a series of commands sent from the higher-level device to the image forming apparatus is completed, an interpreted statement of the analyzed command is sent to the image forming apparatus. Image forming apparatus. 4. The image forming apparatus according to claim 1, wherein each time an analysis of each command from a higher-level device is completed, an interpretation sentence of the command is sequentially transmitted to the higher-level device. 5. The image forming apparatus according to claim 1, further comprising storage means for sequentially storing, when an abnormal command is sent from a higher-level device, the history as a command error history. And transmitting the stored command error history to a higher-level device when transmitting the command interpretation sentence to a higher-level device.