JPH03155974A - Printing system and error recovery method thereof - Google Patents

Abstract

PURPOSE:To contrive to reduce the cost of a printing system and to improve the reliability and workability thereof by serially numbering a printing command in printing page units and, when a printer error occurs, by causing a work station to resend a part of the printing command, of which printing is not over, after the recovery of the system from the error. CONSTITUTION:When an error such as paper jam error occurs in a printer 110, a host computer 100 transmits a printer state-inquiring command to the printer 110. The printer 110, after receiving the command, reads an error information from an error management table 120 and reports it to the host computer 100. Then, the host computer 100 analyzes the information from the printer 110 and informs a user of it. After the user removes the causes of the error, the host computer 100 performs the initialization of the printer 110, thereafter resends a printing command after the serial number of printed pages, which were sent from the printer 110, to the printer 110, and continues printing after the point of time where the error occurred.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention consists of a host computer and a printer, which can communicate with each other, and the host computer sends commands to the printer, and the printer receives commands from the host computer. Execute printing according to the contents of the sent command. The present invention relates to recovery from errors such as paper jam errors that occur in printing systems, particularly in printers such as laser beam printers and wire dot printers.

[Conventional technology]

Conventionally, as described in Japanese Patent Application Laid-Open No. 60-257262, a printer uses a command to hold a print command sent from a host computer until confirmation of completion of paper ejection, which is the normal end of printing processing of the print command. The buffer is stored in the printer as the maximum number of pages that can be printed simultaneously (hereinafter referred to as
(simply referred to as the maximum number of sheets to be held).

When a paper jam error or the like occurs, after error recovery, the print commands after the error occurrence are read from the command buffer and printed again to recover from the error.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, in order to hold the print command until the completion of paper ejection, which is the normal end of the printing process, is confirmed,
A command buffer that can store print commands for the maximum number of sheets that can be held has to be prepared only for error recovery when a paper jam error or the like occurs. Also,
At this time, the required command buffer capacity is considerable, resulting in high costs.

For example, in a laser beam printer with a printing speed of 20 sheets/min, approximately 20 sheets are simultaneously involved in the printing process, so the maximum number of sheets that can be held is approximately 20 sheets. In addition, the print command capacity per page is 30 for one A4 size page.
If it is sent as image data with a density of 0 dots/inch, it will be approximately 1 megabyte. Therefore, in this case, the capacity of the command buffer dedicated to error recovery is approximately 20
It also required megabytes.

An object of the present invention is to solve the problems of the prior art described above, improve the reliability and operability of a printing system, and reduce costs.

[Means to solve the problem]

The following invention is disclosed as a means for achieving the above object.

The first invention restarts the printing process after the printer recovers from an error by assigning a serial number to each printed page in a print command used by the host computer to instruct the printer to print contents, etc., and using the assigned serial number of the printed page. , the printer and the host computer each manage print commands using the serial number of the print page, the printer reports the serial number of the print page that was being printed when an error occurs to the host computer, and the host computer To provide an error recovery method for a printing system, which is carried out by, after error recovery, resending print commands after the page indicated by the serial number of the print page reported by the printer to the printer.

The second invention is.

A means for a host computer to assign a serial number to each print page to a print command for instructing a printer to print contents, etc., and to manage the print commands using the serial number of the attached print page, and when an error occurs, an error management table that stores error information having at least the error type and the serial number of the print page that was being printed;
Error Occurrence 8 - A printer having a means for reporting the error information to a host computer at the time of generation, an abnormality processing control means for controlling each process when an error occurs, and a printer that issues a print command using the serial number of the print page. a means for inquiring the printer about the error status using a command; and a means for resending the print command after the serial number of the print page included in the error information reported by the printer to the printer after error recovery. A printing system is provided, comprising: a host computer having means for performing the printing; and a host computer having the following.

In each of the above inventions, the host computer includes means for instructing the printer to initialize after error recovery and before resending the print command; When the printer detects the error, the printer initializes itself and reports to the host computer that the print command cannot be accepted after the cause of the error has been eliminated but before initialization. It is preferable to include at least one of the following two means.

When an error occurs while printing multiple copies, the printing system according to the present invention reports to the host computer the serial number of the print page that was being printed, as well as information on the number of copies remaining to print that page. and a means for transmitting to the printer, after error recovery, a print command including a print instruction for the remaining number of copies reported by the printer for the page indicated by the serial number of the print page reported by the printer. It is preferable to include a host computer having:

Regarding the implementation of each of the above-mentioned inventions, the host computer assigns a serial number to each print page to the print command for instructing the printer to print contents, etc., and manages the print command using the serial number of the attached print page. The printer and host computer each have means to do so.

[For production]

According to the first invention.

The printer reports the serial number of the print page that was being printed when the error occurred to the host computer, and after the error recovery, the host computer reports the
Resends print commands after the page indicated by the print page serial number reported by the printer. The printer prints pages after the serial number in accordance with the retransmitted print command. That is, the printing process resumes and continues.

Furthermore, in the printing system of the second aspect of the invention, in order to perform printing, the host computer sends a print command to the printer to instruct the print content.

In order to manage the print commands, the print commands are separated into print page units and given a serial number. The serial number is called a print page serial number.

The printer sequentially numbers the pages printed by increasing the number starting from the first page of the printed document. The serial number of the printed page is updated when it is confirmed that the printed paper has been ejected from the printer.

If an error occurs in the printer that requires resending a print command from the host computer to the printer, such as a paper jam error, the printer records the error type and the print page that was being printed at the time of the error in the error management table. Stores error information such as serial number.

The printer notifies the host computer of the occurrence of an error using an error occurrence notification means.

The host computer sends a printer status adjustment command to the printer to check the error status. After receiving this command, the printer reads error information from the error management table and reports the printer status to the host computer using printer status reporting means.

The host computer analyzes the information from the printer and
Notify users.

11. 12. After the user eliminates the cause of the error, the user initializes the printer status.

After initialization of the printer is completed, the host computer resends the print commands after the serial number of the print page sent from the printer to the printer.

The printer that receives the retransmission of the command continues printing from the point at which the error occurred. That is, the printing process resumes and continues.

Note that the host computer sends an instruction to initialize the printer to the printer after error recovery and before resending the print command.

The printer that receives this command to initialize the printer initializes its own state.

With the above operations, the printer can be initialized by the host computer after error recovery and before resending the print command.

Alternatively, the printer detects that the cause of the error has been eliminated, initializes itself, and determines that the print command cannot be accepted when the printer receives a print command before initialization after the cause of the error has been eliminated. This is reported to the host computer, and upon receiving the report, the host computer resends the print command that was reported as not being accepted.

With the above-described operation, the print command can be correctly resent after the printer is initialized.

Further, if an error occurs while printing multiple copies, the printer reports to the host computer the serial number of the page being printed, as well as information on the number of copies remaining to print that page.

After the error is recovered, the host computer sends to the printer a print command including a print instruction for the remaining number of copies reported by the printer for the page with the serial number of the print page reported by the printer.

The printer that receives the print command performs printing according to the received print command. In other words, the printing process resumes and continues regarding the number of copies to be printed.

〔Example〕

A first embodiment of the present invention will be described below.

The configuration of this device is shown in Figure 1.

This device includes a host computer 100 and a printer 110.
It consists of

The host computer 100 includes a communication control section 101, a command control section 102, a storage section 103, a display section 104, and an input section 105.

The communication control unit 101 includes a printer controller 1 which will be described later.
Controls communication with 11. The command control unit 102 analyzes and executes data transmitted and received through communication. Storage unit 103 stores print commands. The display section 104 is
Display messages. Input unit 105 receives input from the user.

The printer 110 includes a printer controller 111, a printer engine 112, and the like.

The printer controller 111 includes a communication control section 113, a command control section 114, a drawing control section 115, an error processing control section 116, a page buffer 117, a printer engine control section 118, a timer control section 119, and an error management table 120. Ru.

The communication control unit 113 controls communication between the host 1 and the computer 100. The command control unit 114 analyzes and controls communication commands and the like.

The drawing control unit 115 performs drawing processing according to the print command received from the command control unit, and stores characters, figures, etc. as dot image data in the page buffer 117.
The printer engine control unit 1 performs print processing for the page buffer 117 that has been generated and has been rendered.
18.

The abnormality processing control unit 116 performs processing when an abnormality occurs using an error management table 120 that stores abnormality information.

The timer control unit 119 controls timers such as a discharge completion monitoring timer.

The printer engine control section 118 converts the dot image data drawn on the page handles 516 and 117 into a signal in a format that the printer engine section 112 can receive, and outputs the signal to the printer engine section 112.

The printer engine section 112 prints on paper using an electrophotographic printing mechanism or a wire dot printing mechanism according to the input signal.

The command control unit 102 of the host computer 100 and the drawing control unit 115 of the printer controller 111 each have print page management means 106 and 121 that manage serial numbers assigned to each print page.

FIG. 2 shows the operation flow on the printer side, FIG. 3 shows the operation flow on the host computer side, and FIG. 4 shows the overall communication sequence.

Host computer 100 and printer controller 11
1 divides the print command into print pages, assigns a serial number to each page, and uses the serial number to issue the print command print page management means (106, 12) for each page.
Manage with 1).

The serial number starts from 0 for the first page of the printed document and increases sequentially. This serial number is called a print page serial number.

The printer controller 111 increments the print page serial number each time paper ejection is completed (sequences 139 and 140). The details of this procedure for confirming the completion of paper ejection will be described later.

The host computer 100 receives a print instruction (
If step 306) is found, the print command is read from the storage unit 103 and sent to the printer controller 111 (step 322) (step 323).

The printer controller 111 receives the command (step 201), and if it is a print command (step 218).
) Print processing (step 219) is started. Print processing (
In step 219), the paper discharge completion detection and drawing control unit 1
15 performs processing such as a page buffer read request to the printer engine control unit.

7. If a paper jam error occurs in the printer engine section 112, the printer engine section 112 notifies the printer engine control section 118 to that effect (step 220).

Upon receiving the notification, the printer engine control unit 118 confirms the error type and then notifies the abnormality processing control unit 116.

The abnormality processing control unit 116 requests the drawing control unit 115 to interrupt the drawing processing and the printing processing (step 202). Further, the print page serial number of the print page that was being printed when the error occurred, the error type being a paper jam error, etc. are stored in the error management table 120 (step 203).

The command control unit 114 creates the contents of the error occurrence notification and issues a transmission request to the communication control unit 113.

Upon receiving the transmission request, the communication control unit 113 transmits the content of this notification to the host computer 100 (step 2
04, sequence 402).

The communication control unit 101 of the host computer 100 receives the error occurrence notification (step 313) and notifies the command control unit 102.

When the command control unit 102 receives the error occurrence notification, it creates a printer status adjustment command to check the error details, requests the communication control unit 101 to send it, and sends the command (step 302, sequence 403).
.

When the communication control unit 113 of the printer controller 111 receives the printer status adjustment command (step 205
), the command control unit 114 reads error information from the error management table 120 in order to create response data to the printer status adjustment command.

After creating this response data (step 206), a printer status report is sent from the communication control unit 113 to the host computer (step 207, sequence 404).

The communication control unit 101 of the host computer 100 notifies the command control unit 102 of the received report (step 303).

19/20° When the occurrence of a paper jam error is determined, the command control unit 102 causes the display unit 104 to display that a paper jam error has occurred (step 313).

Thereafter, an error is occurring (step 301), and an instruction from the user is awaited (step 320, sequence 408).

After eliminating the cause of the error by taking measures such as removing the jammed paper from the printer (sequence 410), the user issues an error recovery instruction from the input unit 105 (sequence 4).
09).

The host computer receives instructions from the user (step 3).
20), the chancel command is sent to the command control unit 114 in order to enable the printer controller 111 to print.
1 and transmits it from the communication control unit 101 (step 321, sequence 405).

In the case of an error such as a paper jam error that requires command retransmission, the error processing described above is performed. If it is any other error (step 324), appropriate error processing corresponding to the error that has occurred is performed (step 325).

When the printer controller 111 receives the cancel command at the communication control unit 113, the printer controller 111
4 (step 211).

Command control unit 114 executes a cancel command. That is, in order to initialize the printer state, the drawing control unit 115 is caused to clear the page buffer 107 (step 212).

Next, in order to notify the host computer 100 that the cancellation has been completed, the command control unit 114 creates a cancellation completion report and causes the communication control unit 113 to transmit it (step 213, sequence 406), and
After sending, the printer is set to a printable state (step 214).

After the host computer 100 receives the cancellation completion report at the communication control unit 101 (step 308), the host computer 100 includes the following information included in the printer status report (sequence 404) in order to reprint from the page after the paper jam error occurred. After reading the print commands after the print page serial number from the storage unit 103 (step 311), they are transmitted to the printer controller 111 (step 312, sequence 407).

The printer controller 111 resumes printing (step 219) according to the received print command (step 218).

As a result, printing starts from the page where the paper jam error occurred.

According to this embodiment, even if a paper jam error occurs in the printer, printing after the error can be resumed without providing a command buffer dedicated to error recovery in the printer. Therefore, the cost of the printing system can be lowered, and the reliability and
Operability can be improved.

Note that, as described above, the procedure for confirming the completion of paper ejection, which is necessary to update the serial numbers of printed pages, will be explained here.

FIG. 5 shows an example of an operation sequence for confirming completion of paper ejection.

Using this diagram, the procedure for confirming the completion of paper ejection for pages with each printed page serial number will be explained.

The drawing control unit 115 instructs the printer engine control unit 118 to read data in the page buffer 117 to the printer engine unit 112 (hereinafter simply referred to as a page buffer read instruction) (sequence 130).
, 133), the timer controller 119 is requested to start the paper discharge monitoring timer (sequences 131 and 134).

The printer engine control unit 118 transmits drawing data to the printer engine unit 112 (sequence 13).
7,138).

When the printer engine unit 112 receives the drawing data, it performs printing and then discharges the paper (sequence 139, 1
40).

After the monitoring time has elapsed, the timer control unit 119 notifies the drawing control unit 115 that the monitoring time has ended (sequences 132, 135, and 136).

The drawing control unit 115 issues a page buffer read request to the printer engine control unit 118 until the printer engine control unit 118 outputs the paper.If there is no abnormality within the time it should take for the link engine unit 112 to output the paper, the paper ejection is completed. , increase the printed page serial number (sequence 141,1
42,143).

The monitoring time varies depending on the printing paper size, and is set when requesting the timer control unit 119 to start the paper discharge monitoring timer.

Next, a second embodiment of the present invention will be described.

The operation flow of the printer controller 111 is shown in FIG.
The operation flow of the host computer 100 is shown in FIG. 7, and the entire communication sequence is shown in FIG.

In this embodiment, instead of using the cancel command used in the first embodiment, the printer itself monitors the error state, and when the paper jam error is eliminated, it automatically initializes and becomes ready for printing. be.

The printer controller 111 is the host computer 1
After sending the printer status report to 00 (sequence 404), the error status is monitored (step 217).
, 601). When it is detected that the cause of the error has been eliminated, the current state is initialized as in the first embodiment at step 602.
) and becomes ready for printing (step 603).

If the error that has occurred does not require retransmission of the command (step 609), other error processing is performed (step 610).

After receiving an error recovery instruction from the user (step 306), if the error requires resending the command (step 324), the host computer 100 reads out the print command after the print page serial number from the storage unit 103 (step 311), and then returns the print command to the printer. Send to controller 111 (
Steps 705.806).

When the printer controller 111 receives the print command, if the cause of the error remains or initialization has not been completed (step 604), it sends a report that the command cannot be accepted to the host computer (step 605).
, sequence 801).

When the host computer 100 receives the command reception failure report (step 702), it waits for a certain period of time and then resends the print command (steps 703 and 705, sequence 804).

If there is no error when the printer controller 111 receives the print command and the initialization has been completed (step 6
04) resumes printing after reporting that the command has been successfully received to the host computer 100 using a command reception report (steps 607 and 608, sequence 8).
05).

In addition to the effects of the first embodiment, the present embodiment has the advantage that the error recovery sequence can be simplified because initialization of the printer state by a cancel command is no longer necessary.

Next, a third embodiment of the present invention will be described.

The operation flow on the printer side will be explained using FIGS. 2 and 6, and FIG. 7 showing the operation flow on the host computer side.

In multi-page printing where multiple copies of one page are printed,
A case will be described in which an error such as a paper jam error occurs that requires retransmission of a print command from the host computer 100 to the printer controller 111.

In the first embodiment and the second embodiment, the error information stored in the error management table 120 by the printer controller 111 when an error occurs includes the remaining number of copies to be printed indicating the remaining number of multi-page print copies that have not been printed yet at the time of the error occurrence. The error information of this embodiment is obtained by adding .

In multi-page printing, the host computer uses the print commands to indicate the total number of copies to be printed for each print page. The printer prints the same content for each print page for the total number of copies to be printed.

If a paper jam error occurs during this multi-page printing, the printer controller 111 calculates and stores the error type, print page serial number, and number of remaining print copies as error information in the error management table 120 (step 203). Here, the remaining number of copies to be printed is a value obtained by subtracting the number of currently printed copies (7·28) for which printing has been completed from the total number of copies to be printed for the print page where the error occurred.

The printer controller 111 is the host computer 1
00, an error occurrence notification is sent to notify that an error has occurred (step 204).

The host computer 100, which has received the error occurrence notification (step 301), sends a printer status adjustment command to the printer controller 111 (step 3).
02).

The printer controller 111 that has received the printer status adjustment command (step 205) reads error information such as the error type, print page serial number, and number of remaining print copies from the error management table 120 (step 206).
After creating the response data, a printer status report is sent to the host computer 100 (step 207).

Host computer 100 reads error information contained in the received printer status report (step 306). It is determined from the error type of the error information that a paper jam error has occurred, and the print command for the page on which to start printing again is determined from the print page serial number. Also, from the remaining number of copies to be printed, the total number of copies to be printed for the page with the actual print page serial number that will be instructed to the printer next can be determined.

After the initialization of the printer controller 111 is completed (steps 602 and 603), the host computer 100 specifies the remaining number of copies for multi-page printing based on the error information, and sends a print command to the printer controller 111. (Step 705).

After receiving this command (step 218), the printer controller 111 resumes printing (step 608).

As a result, printing from the page where the error occurred can be performed even in multi-page printing.

In addition, normal printing also operates without problems by assuming that the number of copies to be printed in multi-page printing is one.

Furthermore, although the number of remaining copies to be printed is stored in the error information, this may be used as the current number of copies to be printed indicating the number of copies that have been printed before the error occurred.

When the current number of printed copies is used, the host computer 100 calculates the remaining number of printed copies by subtracting the current number of printed copies from the total number of printed copies, and the printer controller 11 calculates the remaining number of printed copies.
Give instructions to 1.

In addition to the effects of the first and second embodiments, this embodiment has the following advantages:
This has the effect that error recovery can be performed even in the event of an error during multi-page printing in which a plurality of pages are printed.

FIG. 9 shows a list of commands used in the first, second, and third embodiments. In the figure, 901 is an error occurrence notification, 902 is a printer status adjustment command, and 9
03 is a printer status report, 904 is a cancel command, 905 is a cancellation processing completion report, 906 is a print command, 907 is a command reception failure report, and 908 is a command reception report.

In the first embodiment, 901,902,903°904.9
05, 1 and 906, and in the second embodiment, 901
, 902, 903, 906° 907 and 908 were used.

The third embodiment can be implemented using either the commands of the first embodiment or the second embodiment.

902.904 and 906 are host computer 1
Commands sent from 00 and received by the printer controller 111, 901, 903, 905, 907 and 9
08 is a report sent by the printer controller 111 and received by the host computer 100. In the first embodiment, 902.903 and 904. ．． 905 is a paired sequence, and reports 903 and 904 for commands 902 and 904. In the second embodiment, 902.90
3 and 906, 907, and 908 are paired sequences, and the report for command 902 is 903 and command 90.
The report for 6 is 907.908.

Note that in the above embodiments, a report is used as response data to a command, but it may be realized using a command instead of a response.

Furthermore, the present invention can be similarly applied to errors other than paper jams, as long as they are 1 2 errors that can be recovered by retransmitting a print command from the host computer to the printer.

For example, a door open error occurs when the cover of the printer engine unit 112 is opened during printing, a page buffer parity error occurs when a parity error is detected while reading data from the page buffer 117 to the printer engine unit 112, etc. Applicable to

Further, when an error occurs, the printer controller 111 sends an error occurrence notification (sequence 402) to the host computer 100 to notify the host computer 100 that an error has occurred; In this case, by including the error information and reporting it, the host computer 10
The sequence of the printer status adjustment command (sequence 403) transmitted from 0 to the printer controller 111 and the printer status report (sequence 404) transmitted from the printer controller 111 to the host computer 100 may be omitted.

Further, in the second embodiment, after the printer controller completes the initialization process (step 610), it sends a command acceptance enable command to the host computer 100, and in response, the host computer 100 requests to resend the print command. This may be achieved by starting.

Note that each part in FIG. 1 includes a microprocessor, RAM,
ROM, LSI, logic IC1 electrophotographic printing mechanism,
This can be realized using a wire dot printing mechanism or the like.

〔Effect of the invention〕

According to the present invention, when a printer error occurs, the printer does not recover by itself, but after the error is recovered, the workstation resends print commands for unfinished prints. There is no need to hold a print command until the completion of paper ejection, which is the normal end of the printing process for that print command, is confirmed. That is, in the printing system according to the present invention, it is only necessary to hold the print command until the drawing process is completed.

Generally, it takes about three times as long to complete ejecting one page as it takes to complete the drawing process, so the printing system according to the present invention reduces the print command buffer space to about 1/3 of the conventional one. It can be written as follows. Therefore, there is an effect that the cost of the printing system can be reduced and reliability and operability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the device configuration of the present invention, FIG. 2 is a flowchart showing the processing procedure on the printer side of the first embodiment, and FIG. 3 is the processing procedure on the host computer side of the first embodiment. Flowchart 5 is a sequence diagram showing the paper ejection confirmation procedure in the printer engine section 112, FIG. 6 is a flowchart showing the processing procedure on the printer side in the second and third embodiments, and FIG. 2nd example, 3rd example
FIG. 8 is a flowchart showing the processing procedure on the host computer side of the embodiment. FIG. 8 is a sequence diagram showing the communication procedure between the printer and the host computer of the second embodiment. FIG. , and a list showing commands for communication between the printer and the host 1 to the computer of the third embodiment and a report regarding the commands. 100... Host computer, 101... Communication control unit, 102... Command control unit, 106... Print page management procedure, 110... Printer, 111...
Printer controller 1-roller, 112... Printer engine section, 113... Communication control section, 114... Command control section, 115... Drawing control section, 116... Abnormality processing control section, 117...・Page buffer, 118...
Printer engine control unit, 120...Error management table, 121...Print page management means.

Claims (1)

[Claims] 1. Consisting of a host computer and a printer, which can communicate with each other, the host computer sends commands to the printer, and the printer prints according to the contents of the commands sent from the host computer. In the printing system to be executed, the printer and the host computer each assign a serial number to each print page in a print command in which the host computer instructs the printer to print contents, etc., and use the serial number of the printed page to print the print command. The printer manages print commands, and when an error occurs, the printer reports the serial number of the print page that was being printed to the host computer. After the error is recovered, the host computer reports the print page number reported by the printer to the printer. A printing system error recovery method characterized by resending print commands after a serial number. 2. A printing system consisting of a host computer and a printer that can communicate with each other, the host computer sending commands to the printer, and the printer executing printing according to the contents of the commands sent from the host computer. A method for managing print commands by assigning a serial number to each print page by a host computer to instruct a printer to print contents, etc., and using the serial number of the attached print page, and when an error occurs, an error management table that stores error information having at least an error type and a serial number of a print page that is being printed; a means for reporting the error information to a host computer when an error occurs; an abnormality processing control means for controlling the abnormality processing control means; a means for managing print commands using a serial number of printed pages; a means for inquiring an error state of the printer using a command; On the other hand,
A printing system comprising: a host computer; and means for resending print commands after the page indicated by the serial number of the print page included in the error information reported by the printer. 3. The printing system according to claim 2, wherein the host computer is provided with a function for instructing initialization of the printer after error recovery and before resending the print command. 4. The printing system according to claim 2, wherein the printer includes means for initializing itself when the printer detects that the cause of the error has been eliminated, and means for initializing itself after the cause of the error has been eliminated. 1. A printing system comprising at least one of the following two means: means for reporting to a host computer that the print command cannot be accepted in response to reception of the print command before printing. 5. The printing system according to claim 2, claim 3, or claim 4, wherein when an error occurs in the printer while printing a plurality of copies, the host computer is notified of the printing process when the printer is printing a plurality of copies. In addition to the serial number of a page, a means for reporting information on the remaining number of copies to be printed of that page is provided, and the host computer, after error recovery, informs the printer of the page indicated by the serial number of the printed page reported by the printer. A printing system comprising means for transmitting a print command including an instruction to print the remaining number of copies reported by the user. 6. A printing system consisting of a host computer and a printer that can communicate with each other, the host computer sending commands to the printer, and the printer executing printing according to the contents of the commands sent from the host computer. A printer and a host computer each having means for assigning a serial number to each printed page to a print command used by the host computer to instruct the printer about print contents, etc., and for managing the print commands using the serial number of the attached print page. A printing system comprising: