JPH08310065A - Printing device - Google Patents

Abstract

PURPOSE: To make it possible to combine a paper feed unit with a paper discharge unit which can print in the shortest time by selecting a usable and optimal combination of paper feed unit and paper discharge unit out of paper feed/ discharge units. CONSTITUTION: At first, a main control section 123 selects a paper feed section and a paper discharge section by referring to a paper feed/discharge control table RAM 125. Next, the main control section 123 outputs a read start command signal 141 to a read control section 129, reads a dot pattern from a bit map memory 126, and starts to write in a read FIFO 127. The read control section 129 receives the signal 141 and outputs a print start command signal 142 to a print control section 131. By receiving the signal 142, the print control section 131 starts rotations of a rotary polygon mirror and a photosensitive drum, and operation of a paper conveying system, so that a horizontal synchronous signal 102 incident to the rotation of the rotary polygon mirror and a vertical synchronous signal 103 incident to the rotation of the photosensitive drum are outputted from a printing section 128.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus which receives text data from an external device such as a host computer and prints the text data, and more particularly to a printing apparatus which can select a paper feeding unit and a paper discharging unit optimally. .

[0002]

2. Description of the Related Art Conventionally, control of paper feeding means and paper ejection means (paper feeding unit, paper ejection unit) including options has been performed by an engine controller of a printer.

[0003]

However, the above-mentioned conventional method has some drawbacks as follows. (1) Data sent from the host computer,
Since the relationship between the paper feeding unit and the paper ejecting unit that printed the data was not managed, when performing recovery printing several pages before for jam recovery, the paper feeding unit and ejecting unit used before the jam occurred Exactly the same means as the paper means cannot be used, and when using a special paper such as colored paper or when designating the discharge destination, it is necessary to retransmit the recovery print data from the host computer. (2) If there is an optional paper feeding / paper discharging unit, the CPU power of the engine controller is required to have high performance so that it can be controlled including them. (3) Information regarding the connected paper feed / discharge units, for example, information about the time required for paper feed / discharge for each unit is not managed, and the default setting or the information from the host device (external device) side is not managed. Since the paper feeding and paper discharging unit was selected according to the designation, it was not possible to control to print in the shortest printing time.

[0004]

According to the present invention, in order to solve the drawbacks of the prior art, the control of the paper feeding means and the paper discharging means including the options is performed on the video controller side of the printer having a CPU with higher performance. Therefore, for that purpose, a table is provided in the video controller for managing the paper feed / paper discharge information for the paper. With this management table, it is possible to reproduce the paper feed and paper discharge routes at the time of jam recovery and to select the paper feed and paper discharge routes that realize the shortest printing. In addition, if there is a paper feed or paper discharge route that is ready (operable state) on the management table,
The printing operation can now be performed even if all the paper feeding and discharging means are not ready.

[0005]

Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a printing apparatus showing an embodiment of the present invention. In FIG. 1, 101
Is text data sent from a higher-level device (external device) such as a host computer (not shown), 121 is an input / output buffer for receiving the data, and 122 stores (stores) the data collectively in page units. A page memory, 123 is a main control unit of the printing apparatus, and 12
4 is a font RO storing a character font pattern
M is a RAM 125 is a RAM that stores a paper feeding / paper discharging (paper feeding and paper discharging) management table of the printing apparatus.
Reference numeral 6 is a bitmap memory that stores the text data converted into dot data, and 127 is a FIFO that functions as a buffer when sending the dot data to the printing unit 128.
(First-in-first-out memory) 129 is a read control unit for reading out dot data from the FIFO 127 in synchronization with the horizontal synchronizing signal 102 and the vertical synchronizing signal 103 from the printing unit 128, and 130.
Is a parallel-serial converter for converting the read dot data into serial data and sending it to the printing unit 128, 131 is a print control unit for controlling the printing unit 128, and 132 is an optional supply unit connected to the printing apparatus. An optional unit control unit that controls a paper discharging (paper feeding and discharging) unit, and 133 is an optional paper discharging unit, 13
4, 135 are the paper feeding units 1 which are optionally connected,
It is 2.

FIG. 2 is a view mainly showing a paper feeding / paper ejecting path in a printing apparatus constituted by a printing unit 128 and a paper feeding / paper ejecting unit connected to the periphery thereof. In FIG. 2, 201 is an upper-stage paper feeding unit built in the printing unit 128 as standard, and 202 is a lower-stage paper feeding unit also built in as standard. Reference numeral 203 denotes a laser which is turned on / off (on / off) in response to the dot data sent from the parallel-serial converter 130, and 204 is a rotary polygon mirror which scans and irradiates the laser light onto the photosensitive drum 205. Two
Reference numeral 06 is a developing device, 207 is a transfer roller, and 20
Reference numeral 8 denotes a fixing device, and 209 denotes a face-down sheet discharging unit (hereinafter, also referred to as a sheet discharging unit for the sake of reference together with a sheet discharging unit optionally connected).

Next, the operation of the printing apparatus according to the first embodiment of the present invention will be described. FIG. 3 shows the option unit controller 1
32 and each optional unit, that is, the paper discharge unit 1
33, paper feed unit 1 (134), paper feed unit 2 (1
It is the figure which showed the electrical connection of 35). As shown in FIG. 3, the signal path 104 of the option unit controller 132 is
A sheet feeding unit is connected to, and a sheet discharging unit is connected to the signal path 105. The two paper feeding units are connected in cascade, that is, the paper feeding unit 2 is connected to the option unit controller 132 via the paper feeding unit 1.
Connected to If there is a new paper feed unit 3, the paper feed unit 3 is connected to the paper feed unit 2 as if the paper feed unit 2 was connected to the paper feed unit 1. Similarly, for the sheet discharge unit, when a sheet discharge unit is newly connected, the sheet discharge unit 1
It is similarly connected to the back of 33 (downstream side).

In each optional unit, 331,
Reference numerals 341 and 351 are main control units of the respective units, 332, 342, and 352 are 8-bit (bit) shift registers, and 333, 343, and 353 are selectors. 306 and 308 are serial command lines for sending a command signal from the option unit control unit 132 to each option unit.
Reference numeral 9 is a serial status line for sending a status signal from each option unit to the option unit controller, and 301, 302, 303, 304, 305 are
Signal lines used to check the existence of each option unit, and 310 and 311 are clock signal lines for command and status lines to each option unit.

Immediately after the power is turned on, each option unit enters the connection confirmation phase. That is, first, each output (signal line) 301, 302, 303
To LOW level (step S in FIG. 5).
1). After the elapse of 10 ms, the option unit controller 132 and each option unit input 30
The signal levels of 1, 303, 304, 302 and 305 are checked (step S2 in FIG. 5). The signal line 30
Since 1, 303, 304, 302 and 305 are pulled up to Vcc, they are maintained at HIGH level unless the other party is connected and their outputs are set to LOW level.

First, since the signal lines 301 and 303 are at the LOW level, the option unit controller 132 knows that at least one sheet feeding unit and at least one sheet discharging unit are connected. Also, the signal line 30
Since 2 is a LOW level, the option unit 13
The main control unit 341 of No. 4 knows that at least one sheet feeding unit is connected (downstream) after itself, and opens the selector 343 so that the B input passes. In addition, the main control units 331 and 351 of the option units 133 and 135
Knows that the signal lines 304 and 305 are at the high level and therefore is not connected to anything after itself, and opens the selectors 333 and 353 so that the A input can pass.

As a result, the command / status loop from the signals 306 to 307 and the command / status loop from the signals 308 to 309 are determined as indicated by the thick line in FIG. 4 (step S3 in FIG. 5).

Next, the option unit controller enters a confirmation phase of the number of connected options. First, as shown in FIG. 6, the option unit controller controls the signal line 3
The confirmation commands 601 to 606 are output to 06 and 308 (step S4 in FIG. 5). 601 to 606 have the same contents, and are bit strings such as 10101010. Each option unit does not perform any operation in response to this confirmation command.

In the signal line 306, the contents of the register 352 (previously set to 0 by the main control unit 351) and the contents of the register 342 (also the main control unit 341) as shown in FIG. Previously set to 0 by), and 601
Appears. The option unit controller is 601
Only the input is detected, and it is known that the two option units are connected as the paper feeding unit (step S5 in FIG. 5). Similarly, the signal 309 is 6
It is detected that 04 and 605 have returned, and it is known that one option unit is connected as a paper discharge unit (step S5 in FIG. 5). In this embodiment, a maximum of three paper supply / discharge units are connected.

Next, the option unit controller confirms what kind of option unit is connected. As is clear from the above description, the signal line 30
When a command is issued to 6, 308, signal lines 307, 309
The contents of the registers 342, 352, 332 appear on the screen, and the mechanism for sending to the option unit controller is used. This mechanism will be described in more detail with reference to FIG.

The option unit controller 132 always outputs a command to each option unit every 10 ms. The command is transmitted to each option unit through signal lines 306 and 308. For example, command 8
01 is sent to the register 352 of 135, and the command 80
2 is sent to the register 342 of 134, and each control unit 35
Passed to 1,341.

Each option unit sends the reply status to the command to each register 342, 352, 332 by 10 ms after the next command is sent.
To load. The contents of these registers (that is, the response status) are synchronized with the signal lines 30 in synchronization with the clocks 310 and 311 for the next command sent 10 ms later.
It is returned to the option unit control unit 132 through 7, 309. That is, the response status to the command from the option unit controller 132 returns after 10 ms.

More specifically, the option unit controller 132 outputs commands 801, 802, 821 inquiring about the type of each option unit (step S6 in FIG. 7). After the lapse of 10 ms, the next command (a command instructing to do nothing if it is not necessary) may be output and the response status 811, 812, 841 from each option unit may be obtained. The answer status is returned according to the correspondence between the predetermined code and the option unit, and is, for example, "10000001" indicating the optional three-stage paper feeding unit.

In addition, in the same manner, the same command is output, and detailed information of each option (for example, for the paper feed unit, the number of paper feed stages and the respective paper capacity, paper size, presence / absence of paper, whether or not the paper feed start is possible) For the paper discharge unit, the number of paper discharge stages, paper discharge capacity, presence / absence of paper, information on whether or not paper can be discharged are inquired) and the obtained status information is sent to the main controller 123 (see FIG. 1). Report (Figure 7)
Step S8). The main controller 123 loads the option unit information received from the option unit controller 132 into the paper feeding / paper ejection management table RAM 125. The main control unit 123 also inquires of the print control unit 131 so that an upper sheet feeding unit (upper sheet feeding unit) 201 and a lower sheet feeding unit (lower sheet feeding unit) 202 that are standardly attached to the printing unit 128. , And the face-down paper discharge unit (paper discharge unit) 209, the same information is obtained and similarly loaded in the paper supply / paper discharge management table RAM 125.

As a result, the supply / discharge management table RAM1
The information shown in FIGS. 9 and 10 is stored in 25. In FIG. 9, the column 901 shows the type of paper feeding unit, the column 902 shows the respective paper size,
The column 903 indicates the presence or absence of each sheet, and 904 indicates whether or not each sheet can be fed (ready). Actually, information is represented by a bit string (1010 etc.). Further, in this embodiment, the paper feed path length (that is, the time required for paper feed) until reaching the photosensitive drum 205 is registered in order from the top. In addition, "No" in the last column of 901 indicates that there is no sheet feeding unit other than these.

In FIG. 10 as well, the column 1001 indicates the type of sheet discharge unit, the column 1002 indicates the sheet discharge capacity, the column 1003 indicates the presence or absence of discharged sheets, and the column 1004 indicates. Indicates whether each can be ejected.
The information in the feeding / ejection management table RAM 125 is rewritten by the main control unit 123 every moment according to the state of the feeding / ejection command. The same information is also reported to a host computer (not shown) via the data line 101.

Now, the operation of the embodiment of the present invention after this will be described based on the actual printing operation. Data coming from the host computer (not shown) through the data line 101 is composed of a character code and a control code. The character code is a code that literally indicates the character to be printed, and the control code is the character, the size, and the font to print the character, and the size of the paper to be printed. Designate and specify the number of copies.

The character code and control code are then stored in page memory 122 page by page. Next, the main control unit 123 reads it out in order, inquires from the character code and the control code to the font ROM 124, performs an operation such as enlargement if necessary, and then develops it in the bitmap memory 126 as a dot pattern. When the development of the dot pattern for one page is completed, the printing operation is finally started. As an example, let us consider a case in which eight copies are output on A4 size paper and output. This may be designated by a control code or may be designated by an operation panel on a printer (not shown).

First, the main control section 123 refers to the sheet feeding / ejection management table RAM 125 to select the sheet feeding section or the sheet ejection section. In the states shown in FIGS. 9 and 10, all of the paper feed / discharge units are in the ready state. Since the sheet size is A4, the standard upper-stage sheet feeding section with the shortest sheet feeding time is selected as the sheet feeding section. This is because the time required for printing can be shortened.

As the paper ejecting unit, the option paper ejecting unit 133 is selected because eight copies are made. If one copy is to be made, the standard face-down sheet discharge section with the shortest sheet discharge time is selected. First, the main control unit 123
Informs the print controller 131 that the standard upper sheet feeder is selected and the option unit controller 132 selects the sheet discharge unit 133 to use all eight-stage sorters.

Next, the main control section 123 outputs the read start command signal 141 to the read control section 129, reads the dot pattern stored from the bit map memory 126, and starts writing to the FIFO 127. Upon receiving the signal 141, the read control unit 129 outputs the print start command signal 142 to the print control unit 131. In response to the signal 142, the print control unit 131 starts the rotation of the rotary polygon mirror 204, the rotation of the photosensitive drum 205, and the start of the operation of the paper transport system. Sync signal 102
Then, the vertical synchronizing signal 103 is output according to the rotation of the photosensitive drum.

The read control unit 129 synchronizes with the synchronizing signals 102 and 103 (which are signals used for horizontal and vertical synchronization when the read control unit 129 sends image dot data to the printing unit 128). A dot pattern is read from a FIFO (First In First Out Memory) 127, and the read dot pattern is converted into a serial signal by the parallel-serial converter 130, and the printing unit 12
8, the laser 203 is turned ON / OFF according to HIGH and LOW of this signal, scanned, and image data is written on the photosensitive drum.

On the other hand, the print control unit 131 feeds the printing paper from the upper paper feeding unit 201 in the meantime and feeds it to the front of the paper feeding unit registration roller 210, and the front end of the paper and the photosensitive drum 205. Rotate the paper feed unit registration roller 210 at the timing when the leading edges of the image patterns match,
The printing paper is fed to the position of the photosensitive drum 205. At this time, in the paper feed management table shown in FIG. 9, from the start of paper feed until the paper has finished passing through the paper feed unit registration rollers 210, as shown in FIG. ,
The standard lower-stage paper feeding unit cannot feed paper (the next paper cannot be fed), and as shown in FIG.
When it finishes passing 0, it returns to normal.

The option paper feed command is allowed because the paper can be moved up to the front of the option paper feed unit registration roller 211. However, if paper is fed from the optional paper feeding unit at this time, it will be disabled (the next paper cannot be fed).

As described above, information about the above-mentioned state of the paper feeding unit is sent from the print control unit 131 to the main control unit 123 every moment, and is reflected in the management table RAM 125.

The paper sent to the photosensitive drum 205 is printed and fixed by the fixing device 208. Meanwhile, the main controller 123 issues a paper discharge operation start command to the option controller 132, and the option unit controller 1
Reference numeral 32 causes the paper discharge unit 133 to start the paper discharge operation to the sorter A. In this case, in the paper discharge management table shown in FIG. 10, until the printed paper enters the paper discharge unit 133, the standard face-down paper discharge unit cannot discharge paper, as shown in FIG. Paper output unit 1
When it enters 33, it changes as shown in FIG. The paper is discharged to the sorter A of the paper discharge unit 133, and when the paper discharge is completed, the paper can be discharged as shown in FIG. Next, it goes without saying that the printed sheet is sent to the sorter B and the printing is sequentially repeated up to the sorter H.

Next, a case will be described in which B4 is specified as the paper size and one copy is designated. In this case, the optional paper feed unit B of the optional paper feed unit 1 (134)
Is selected as the paper feed unit, and the standard face-down paper discharge unit with the shortest paper discharge time is selected as the paper discharge unit. Since the other operations are the same below, only the sheet conveyance timing will be described.

When the expansion of the image dot data into the bit map memory 126 is completed, the main control section 123 notifies the option unit control section 132 that the paper feed section B of the optional paper feed unit 1 has been selected, and the printing is performed. The control unit 131 is notified that standard face-down sheet ejection is to be performed.

When printing is started, a paper feed start command is issued from the main controller 123 to the option unit controller 132,
Paper is fed from the paper feed section B of the option paper feed unit 1 and reaches the registration rollers 210. From the start of paper feeding, the paper feeding / ejection management table changes as shown in FIG. The registration roller 210 is activated and the paper is exposed to the photosensitive drum 2.
When it is sent to 05, the table changes as shown in FIG. 13B, indicating that there is a sheet feeding unit that can perform the next sheet feeding. The state shown in FIG. 13C is obtained until printing is completed and paper discharge is completed.

As described above, the supply / discharge management table 12
By referring to No. 5, it is possible to integrally control the feeding and discharging of the standard unit and the optional unit.

(Embodiment 2) FIG. 14A shows that a paper feed jam or the like has occurred in the optional paper feed unit 2 and paper cannot be fed. In this case, since the optional paper feed unit 1 can be used for paper feed, the main control unit 123 switches the paper feed to the optional paper feed unit 1 for printing.

When a jam or the like occurs in the paper discharge unit 133 as shown in FIG. 14B and the paper cannot be discharged, the main controller 123 discharges paper to the standard face-down paper discharge unit 209 to print. I do.

(Third Embodiment) In the first embodiment, the combination of the short feeding / discharging time is selected as the feeding / discharging unit, but an optional connected feeding / discharging unit may be selected.

(Embodiment 4) For example, when paper is fed from the standard paper feed unit and printing is being performed and the paper in the paper feed unit runs out, and automatic paper feed is specified Automatically has good throughput conditions,
That is, in the fourth embodiment, the sheet feeding unit A of the option sheet feeding unit 1 that requires a shorter time for sheet feeding is selected next.

(Embodiment 5) When an optional paper feeding unit or paper discharging unit is added, the management table RA is naturally used.
Although the contents of M125 are added, if there is no instruction for feeding / discharging from the above-mentioned device or an operation panel (not shown), a mode in which the added sheet feeding unit or discharging unit is preferentially selected as a default May be added.

(Embodiment 6) For example, when paper is fed from the standard paper feed unit and printing is performed, and the paper in the paper feed unit runs out, or when automatic paper feed is not designated The temporary printing is suspended until the paper in the paper feeding unit is fed.

Further, even in the automatic paper feed mode, it may be necessary to recover the printing before the transition to the automatic paper feed mode due to a paper jam. In this case, the paper feeding unit selected at the time of previous printing may be selected and reprinted.

This is achieved by registering the information of the unit fed for each sheet and the sheet feeding / ejection management table RAM 125 shown in FIG. FIG. 15 shows an example thereof. FIG. 15 shows a table in which information for 10 sheets is managed. In the table, 1501 indicates a sheet number indicating the order of sheets to be printed, 1502 indicates sheet size information to be printed, and 1503 indicates sheet feeding. 1504 indicates a unit to be ejected, 1504 indicates information indicating whether or not a sheet feeding unit is designated, 1505 indicates a unit to be ejected, and 1506 indicates information indicating whether or not a sheet ejecting unit is designated. Numeral 1507 indicates information indicating whether or not the paper is printed and the paper discharge is completed. 1507
Then, "completed" means that it has been completed, and "unfinished" means that it has not been printed, or that it has been printed but has not been ejected yet.

Therefore, it is necessary to recover the information that does not have 1507 when a jam occurs. Also, since all the information that is completed in 1507 has been completed, it is possible to rewrite it, and therefore, the sheet numbers 1501, 1, 2, and 3 in FIG. 15 are completed, so the 11th, 12th, and 13th sheet information, respectively. Is used in a circular manner such that is written. In FIG. 15, for example, if a jam is detected at the line 1508, that is, at the eighth sheet, recovery printing after the jam processing is performed on the fourth to eighth sheets, and the sheet feeding designation and the sheet ejection are performed in this table, respectively. For the paper for which the paper designation is “present”, the printing work is performed according to the designation.

At this time, if the paper cannot be fed from the designated paper feeding unit, it waits until the paper feeding unit is ready to feed paper. It will wait until the paper can be discharged to the paper discharge unit.

(Embodiment 7) FIG. 16 shows that the option sheet feeding unit 2 cannot be used as a sheet feeding means due to a failure, and the option sheet discharging sorter cannot be used as a sheet discharging means. Even in such a case, if the defective feeding / discharging means is not designated as the data in the feeding / discharging means as data, as is clear from the feeding / discharging route of FIG. Since the route for feeding and printing on the standard face-down sheet discharge unit can be used, the main control unit 123 selects this route and prints.

[0047]

As described above, according to the present invention,
It has become possible to manage the text data sent from the host computer and the optimum paper feed / discharge route. Specifically, (1) Even if not all of the paper supply / discharge units are ready, printing is possible if there is a combination of units that can supply / discharge paper. (2) It is possible to combine the paper feed / discharge units for printing in the shortest time. (3) It is possible to combine the feeding / discharging means so as to maintain continuous printing to maximize the printing throughput. (4) Payroll required for recovery printing during jam recovery
The paper ejection route can be reproduced, and a more flexible printer can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a paper supply / discharge system of the printing apparatus.

FIG. 3 is a diagram showing connection of option units.

FIG. 4 is a connection diagram of an option unit showing establishment of a signal route.

FIG. 5 is a flowchart showing an operation of an option unit controller.

FIG. 6 is a timing chart (paper feeding system) showing the exchange of signals between the option unit controller and the option unit.

FIG. 7 is a flowchart showing an operation of an option unit controller.

FIG. 8 is a timing chart (paper discharge system) showing the exchange of signals between the option unit controller and the option unit.

FIG. 9 is a diagram illustrating a paper feed management table.

FIG. 10 is a diagram illustrating a discharge management table.

FIG. 11 is a diagram for explaining the movement of the paper feed management table.

FIG. 12 is a diagram for explaining the movement of the paper discharge management table.

FIG. 13 is a diagram for explaining the movement of the paper supply / discharge management table.

FIG. 14 is a diagram for explaining the movement of the paper supply / discharge management table.

FIG. 15 is an example of a table for managing the relationship between the paper and the paper supply / discharge unit.

FIG. 16 is a diagram illustrating a paper feed / paper discharge management table of another embodiment.

[Explanation of symbols]

 123 Main Control Unit 125 Feed / Discharge Management Table 128 Printing Unit 131 Printing Control Unit 132 Option Unit Control Unit 133 Option Paper Discharging Units 134, 135 Option Paper Feeding Units 1, 2

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichiro Maekawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yutaka Tokura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yoichi Toyokura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jun-ichi Kimizuka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Akihiro Nakamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuichi Higuchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (12)

[Claims] 1. In a printing device for receiving text data from an external device such as a host computer and printing it, a paper feeding unit and a paper discharging unit, which are installed as standard equipment, and a paper feeding unit and a paper discharging unit, respectively, are optionally provided. A printing apparatus, wherein an optimum combination of a paper feeding unit and a paper discharging unit that can be added and is usable is selected and printing is performed. 2. The printing apparatus according to claim 1, wherein the optimum combination is a combination of a paper feeding unit and a paper discharging unit that requires the shortest time for feeding and discharging. Printing device. 3. The printing apparatus according to claim 1, wherein the optimum combination is the number of print sheets provided as information from an external device or an operation panel on the printing device,
Based on the information such as the paper size, when the paper feeding unit and the paper discharging unit are designated from the external device, the designation is performed, and when there is no designation, the printing device side selects. Printing device. 4. The printing apparatus according to claim 1, wherein the optimum combination is a combination that allows the printing apparatus to maintain the highest printing throughput. 5. The printing apparatus according to claim 1, wherein when there are a plurality of pieces of text data from the external apparatus and they have the same paper size, the one that can maintain the maximum throughput is fed from the same paper feeding unit. A printing device characterized by printing on paper. 6. The printing apparatus according to claim 5, wherein when there is no more paper in the paper feeding unit that is currently being fed and more paper is to be continuously printed, the paper feeding unit with the best throughput is selected. A printing device characterized by selection. 7. The printing apparatus according to claim 1, wherein when an optional paper feeding unit and paper discharging unit are added, and when there is no instruction, the added optional paper feeding unit and paper discharging unit are prioritized. A printing device characterized by being used. 8. The printing apparatus according to claim 1, wherein even if there is a combination of usable sheet feeding units and sheet discharging units which cannot be used, another sheet feeding unit,
A printing apparatus that performs a printing operation when a paper discharge unit can be substituted and a supply / discharge path required for printing can be secured. 9. The printing apparatus according to claim 1, wherein when performing a recovery printing retroactively when a jam occurs, when a paper feeding unit and / or a paper discharging unit is designated during the recovery printing, a jam occurs. A printing apparatus that performs recovery printing as specified before even if is in the automatic paper feed / discharge mode. 10. The printing apparatus according to claim 9, wherein in the jam recovery printing, if the designated paper feed unit cannot feed the paper, the paper feed unit waits until the paper feed unit is ready to feed the paper. If the paper cannot be discharged to the paper discharge unit, the printing device waits until the paper can be discharged to the paper discharge unit. 11. A printing apparatus for receiving text data from an external device and printing the text data, a paper feeding unit and a paper discharging unit installed as standard, a paper feeding unit and a paper discharging unit optionally connected, and the option. Detecting means for detecting at least the number and status of the paper feeding units and the paper discharging units, optional paper feeding units detected by the detecting means, status information of the paper discharging units, and standard paper feeding units, paper discharging units And a selection unit that refers to the status information stored in the memory unit and selects a desired combination of the paper feed unit and the paper discharge unit according to the print command. Printing device. 12. The printing apparatus according to claim 11,
Among the status information stored in the memory means, the availability of the paper feed unit and the paper discharge unit, the presence / absence of paper fed from the paper feed unit, and the presence / absence of paper stored in the paper discharge unit are determined according to the progress of printing. A printing apparatus that is updated and can detect the presence or absence of a jam.