JP3067004B2 - Printer control device and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling paper feed in a printer and a control method therefor.

[0002]

2. Description of the Related Art Conventionally, in a non-impact printer such as an electrophotographic printer, a charged photosensitive drum is irradiated by a light source to form an electrostatic latent image on the surface thereof, and the formed toner image is printed on paper. It is designed to transfer and fix.

FIG. 2 is a schematic structural layout diagram of a sheet transport section in an electrophotographic printer generally known as a non-impact printer. In FIG. 2, in this printer, cut sheets 30 cut and stacked one by one in a cassette 31 are sent out one by one into a sheet conveying path 42 by a hopping roller 33, and are printed on the way. After being fed to the stacker 32 and stored therein, an entrance sensor 6 for detecting the paper 30 taken out from the cassette 31 is provided in the middle of the paper transport path 42.
A registration roller 34 and a pressure roller 35 constituting a first sheet conveying means, a printing section 40 for printing on the sheet 30, and an exit sensor 7 for detecting the sheet 30 discharged from the printing section 40. And a discharge roller 37 and a discharge roller 38 constituting the second sheet conveying means. The printing unit 40 includes a photosensitive drum 41, a primary charger 39, an LED head 19, a developing unit 27, a transfer roller (transfer unit) 28, a fixing roller (fixing unit) 22, a backup roller 36, and the like.

FIG. 3 is a block diagram of a print control circuit in the electrophotographic printer shown in FIG. 2, and FIG. 4 is a time chart of a sheet transport section in the printer. In addition,
In FIGS. 3 and 4, the same reference numerals as those in FIG. 2 denote members corresponding to the members shown in FIG. First, the configuration of the print control circuit in FIG. 3 will be described. In FIG. 3, reference numeral 1 denotes a print control unit. The printing control unit 1 includes a microprocessor, a ROM, a RAM, an input / output port, a timer, and the like, and is provided inside the printing unit 40. The entire printer unit is sequence-controlled by a control signal 10 and a video signal 11 from a higher-level controller (not shown) to perform a printing operation. The print control unit 1 includes a driver 2 and a developing / transfer process motor ( PM) 3, driver 4, paper feed motor (P
M) 5, entrance sensor 6, exit sensor 7, paper remaining amount sensor 8, paper size sensor 9, LED head 19, fixing roller 22, charging high voltage power supply 25, developing high voltage power supply 25a,
The transfer high-voltage power supply 26, the developing device 27, the transfer roller 28, the fixing device temperature sensor 29, the primary charger 39, and the like are connected.

Next, the operation of the electrophotographic printer will be described with reference to FIGS. First, when the print control unit 1 receives a print instruction by a control signal 10 from a higher-level controller (not shown), the print control unit 1 first sets a temperature range in which the fixing roller 22 including the heater 22 a can be used by the fixing unit temperature sensor 29. Is detected, the heater 21a is energized by the signal 21 if the temperature is not within the temperature range, and the fixing roller 22 is heated to a usable temperature.
Next, the developing / transfer process motor (PM) 3 is rotated via the driver 2, and at the same time, the charge signals 23, 23
a, the charging high-voltage power supply 25 and the developing high-voltage power supply 25a
Is turned on to charge the primary charger 39 and the developing device 27.

Further, the type of the paper 30 set in the cassette 31 is detected by the paper remaining amount sensor 8 and the paper size sensor 9, and the paper feeding corresponding to the paper 30 is started. Here, the paper feed motor (PM) 5 can rotate bidirectionally via the driver 4,
First, the sheet rotates in the reverse direction, and conveys the sheet 30 from the inside of the cassette 31 by the hopping roller 33 to the position of the registration roller 34 and the pressure roller 35 where the sheet suction is detected by the entrance sensor 6. At this time, after the sheet 30 is detected by the entrance sensor 6, the sheet is fed an extra amount by a preset amount so that the leading end of the sheet 30 contacts the registration roller 34.

Next, the paper feed motor 5 is switched to normal rotation, the driving of the hopping roller 33 is stopped, and the registration roller 34 is driven. Then, by this driving, the paper 30 is moved to the registration roller 34 and the pressure roller 3.
5 and is conveyed into the printing unit 40 and sent between the photosensitive drum 41 and the transfer roller 28 in the printing unit 40.

Here, the photosensitive drum 41 and the fixing roller 22
Since the discharge rollers 37 and 38 are driven by the developing / transfer process motor 3, the paper 30 passes through the contact portion between the photosensitive drum 41 and the transfer roller 28 and contacts the fixing roller 22 and the backup roller 36. It is sequentially fed to the contact portion by driving the registration roller. The sheet 30 that has reached the fixing roller 22 is now sandwiched between the fixing roller 22 and the backup roller 36, and is driven by the driving force of the fixing roller 22 and the driving force of the discharge rollers 37 and 38. It will be transported. Then, the sheet 30 that has passed the portion of the fixing roller 22
Is detected by the outlet sensor 7 and the discharge roller 3
The paper passes through the portions 7 and 38 and is discharged to the stacker 32.

When the paper 30 reaches the position between the photosensitive drum 41 and the transfer roller 28 in the printing unit 40, the printing control unit 1 sends a timing signal 12 (line timing signal, raster timing signal ) And the video signal 11 is received. Then, in the upper controller, the print data is edited for each page and sent to the print control unit 1 as a video signal 11 for each print line. The video signal 11 received by the print control unit 1 is transmitted to the LED head 19 as an actual print data signal 18. Then, when receiving the video signal 11 for one line, the print control unit 1
The latch signal 17 is transmitted to the D head 19, and the actual print data signal 18 is held in the LED head 19. And
Before receiving the next data from the host controller, the print control unit 1 transmits the print drive signal 13 to the LED head 19 and outputs the actual print data signal 18 held by the LED head 19.
Print. Reference numeral 18a indicates the actual print data using an LED.
This is a clock signal to be transmitted to the head 19.

In this manner, the transmission and reception of the video signal 11 are performed for each print line, and the information printed by the LED head 19 is converted into a latent image as a dot having an increased potential on the photosensitive drum 41 charged to a negative potential. Then, the toner for image formation charged to the negative potential is attracted to each dot by an electric attraction force, and a toner image is formed.

Thereafter, the toner image is sent to a transfer section,
The transfer high voltage power supply 26 having a positive potential according to the transfer signal 24
Is turned on, and the transfer roller (transfer device) 28 transfers the toner image onto the paper 30 passing through the gap between the photosensitive drum 41 and the transfer roller 28. The sheet 30 having the image transferred here is conveyed in contact with a fixing roller (fixing device) 22 having a built-in heater 22a, and the toner image is fixed on the sheet 30 by the heat of the fixing roller 22. Thereafter, as described above, the sheet passes through the discharge rollers 37 and 38 and is discharged to the stacker 32.

The print control unit 1 is adapted to detect the paper size sensor 9 and the entrance sensor 6 and to control the paper 30
The voltage from the transfer high-voltage power supply 26 is applied to the transfer roller 28 only while the sheet passes through the transfer roller 28. And
When printing is completed and the paper 30 passes through the exit sensor 7,
The printing on the developing device 27 by the charging high-voltage power supply 25 is completed, and at the same time, the rotation of the developing / transfer process motor 3 is stopped. Thereafter, the above operation is repeated.

FIG. 5 shows the above electrophotographic printer.
FIG. 6 shows an example of a flowchart for processing a paper feed abnormality. FIG. Therefore, using the flowchart shown in FIG. 5, the following (1) to (1) to FIG.
The case (5) will be described. First, an outline of the processing method here will be described. In the above-described printing operation, the entrance sensor 6 and the exit sensor 7 generate detection outputs by turning on and off as shown in FIG. If the sheet feeding operation is normal, these detection outputs are output at timings and widths within a predetermined range depending on the length of the sheet 30 used for each time and the distance between the rollers. Then, the abnormality detection here is based on the conveyance error of the sheet 30 (hereinafter referred to as “jam (JA)” based on the determined timing time.
M)), and in order to prevent the paper from being left in the printer in the event of a paper jam, the motor 3 for the development / transfer process and the paper feed motor 5 have a length of (the length of the paper 30 + the extra length). Is rotated, the paper 30 is taken out of the printer, a display for issuing a recommendation to the operator is made, the printer is stopped, and thereafter, the operator's intervention is waited.

(1) When a paper jam occurs at the entrance where the paper 30 is taken out of the cassette 31 by the hopping roller 33: First, when the print control unit 1 receives a print instruction by the control signal 10 from the host controller, the paper feed is performed. The motor 5 is driven (Step S1).
Then, in step S2, the entrance sensor 6 detects whether the paper 30 has been conveyed and monitors whether it is turned on. here,
If the entrance sensor 6 is not turned on after a predetermined period of time, the print controller 1 determines that a jam has occurred at the entrance (step S3), and in step S4, develops and transfers the paper by the length of the sheet. After the process motor 3 and the paper feed motor 5 are driven, a display for issuing a recommendation to the operator is displayed, and then the printer is stopped including the energization of the fixing roller 22 (step S5), and the operation of the operator is waited for thereafter. . In this case, since continuous printing is impossible, the control unit 1 keeps informing a higher-level controller (not shown) that the currently performed printing is not normally completed. On the other hand, since printing on the next sheet 30 has not been started, the host controller saves the data to be printed on the next sheet 30 as it is, stops, and waits for recovery by the operator. The recovery by the operator here is performed as follows. First, since the display is a jam display at the entrance, the operator checks the presence or absence of the paper 30 in the cassette 31, and if there is no paper, sets it. Then, a reset operation (not shown) is performed. Then, the print control unit 1 performs the initial operation again. In the initial operation, it is checked whether or not the entrance sensor 6 and the exit sensor 7 are off, and further, the primary charging of the photosensitive drum 41 and the heating process to the printable temperature of the fixing roller 22 are performed. When the preliminary operation for enabling these printings is performed and completed, the status indicating that the printing is possible is sent to the host controller side. That is, the jam release by the operator is completed in this state. Then, the host controller inputs the printable state from the print control unit 1 and sends the held print data that has not been printed due to the previous jam occurrence to the print control unit 1 again, and prints with the jam. Reprint the failed data.

(2) When a paper jam occurs in the printing unit 40: If the entrance sensor 6 confirms the conveyance of the paper 30 in step S2, then the exit sensor 7 detects the conveyance of the paper 30 in step S7. Monitor if it is turned on. Here, if the exit sensor 7 is not turned on even after the set time has elapsed, the print control unit 1 determines that a jam has occurred in the print unit 40 (step S7). In step S4, the developing / transfer process motor 3 and the sheet feed motor 5 are driven by the length of the sheet.
After the display for issuing a recommendation to the operator is made, the printer is stopped (step S5), and the recovery operation by the operator is awaited thereafter. The recovery by the operator here is performed as follows. First, since the display is a jam display of the printing unit 40, the operator opens a cover (not shown) to check the presence or absence of the paper 30 in the printing unit 40, removes the paper 30, and closes the cover. The reset signal is output to the print control unit 1 by opening the cover of the printer.
A switch mechanism (not shown) is mounted, and the print control unit 1 performs the initial operation again by closing the cover. In the initial operation, the entrance sensor 6, exit sensor 7
Is checked, and the primary charging of the photosensitive drum 41 and heating processing of the fixing roller 22 to a printable temperature are performed. When the preliminary operation for enabling these printings is completed and completed, the status indicating that the printing is possible is sent to the host controller. That is, the jam release by the operator is completed in this state. When the host controller inputs the printable state from the print control unit 1, it sends the held print data that did not end normally due to the previous jam occurrence to the print control unit 1 again. This allows the printer to:
Reprint data that could not be printed due to jam.

(3) When a plurality of inhaled sheets 30 are sent in a superposed state, that is, when “double feed” is performed: Generally, “double feed” means that the sheet 30 stored in the cassette 31 This is a phenomenon in which static electricity accumulates due to mutual friction, the uppermost sheet 30 to be sucked adheres to the second sheet 30 due to static electricity, and a plurality of sheets are conveyed simultaneously. Then, it is assumed that the sheet 30 conveyed from the cassette 31 is conveyed by half the sheet length, and then the next sheet 30 is stuck, and thereafter the sheet 30 is double fed. Then, when the leading end of the sheet 30 passes through the entrance sensor 6, it is confirmed that the entrance sensor 6 is on (step S2), and then it is confirmed that the exit sensor 7 is on (step S6), and the process proceeds to step S8. In this case, when the ON of the entrance sensor 6 is confirmed, the printing unit 40 prints the sheet 30 conveyed to the photosensitive drum 41 side. However, since the paper 30 here is overlapped and fed halfway, the length of the conveyed paper is 1.5 times as long as the normal operation. For this reason, the specified time T (this time is the paper transport speed V [mm / s], the paper length L
Even if T = L / V + α (α is an extra time for obtaining a margin) elapses from [mm], the entrance sensor 6 is not turned off (step S).
8, S9). Then, the printing control unit 1 detects this state as "printing section jam", drives the developing / transfer process motor 3 and the sheet feeding motor 5 by the length of the sheet in step S4, and then makes a recommendation to the operator. After the display to be issued is made, the printer is stopped (step S5), and the operation of the operator is awaited thereafter. Also in this case, the print control unit 1
Since it is impossible to continue printing, the printer continues to notify the host controller (not shown) that the currently executed printing is not normally completed. On the other hand, since the printing has not been completed normally, the host controller saves the currently printed data as it is, stops the operation, and waits for a recovery operation by the operator. The restoration work in this case is described in (2) above.
The processing is performed in the same manner as in the case of.

(4) When a jam has occurred at the exit portion: After the entrance sensor 6 is turned off (step S9), the exit sensor 7 is not turned off after the set time has elapsed (step S9).
12, S13), the print control unit 1 detects the "ejection unit jam", and drives the developing / transfer process motor 3 and the paper feed motor 5 by the length of the paper in step S4.
After that, after displaying the recommendation to the operator,
The printer is stopped (step S5), and waits for the operator's work thereafter. In this case as well, since the printing cannot be continuously performed, the printing control unit 1 continues to notify the host controller (not shown) that the currently performed printing is not normally completed. On the other hand, since the printing has not been completed normally, the host controller saves the currently printed data as it is, stops the operation, and waits for a recovery operation by the operator.
Note that the recovery work in this case is processed in the same manner as in the case of the above (2). Further, even if the outlet sensor 7 is turned off (step S12), if this is not performed within the specified time (step S14), the processing is performed as "ejection section jam". On the other hand, if the printing is performed within the specified time, the developing / transfer process motor 3 and the paper feed motor 5 are driven by the length of the paper, the paper 30 is conveyed to the stacker 32, and printing is completed ( Step S1
5).

(5) When a paper jam occurs in the printing unit 40 (when the paper is less than the specified size): When the short paper 30 is erroneously set in the cassette 31, the leading end of the paper 30 is detected by the entrance sensor. 6, after the entrance sensor 6 is turned on (step S2), the exit sensor 7 is checked.
Is checked (step S6), and the process proceeds to step S8. In this case, when the ON of the entrance sensor 6 is confirmed, the printing unit 40 prints the sheet 30 conveyed to the photosensitive drum 41 side. However, since the short sheet 30 is erroneously set in the sheet 30, the time when the entrance sensor 6 is turned off is shorter than the specified time T described above. From this time, the length of the sheet 30 is calculated and compared with a specified value (steps S10 and S11). Here, since the length of the paper 30 is other than the specified value, the print control unit 1 detects this state as “paper size error printing unit jam”, and in step S4, the development / transfer process is performed by the length of the paper. Then, the printer motor 3 and the paper feed motor 5 are driven, and after a display for issuing a recommendation to the operator is made, the printer is stopped (step S5) and the operation of the operator is awaited thereafter. In this case as well, since the printing cannot be continuously performed, the printing control unit 1 continues to notify the host controller (not shown) that the currently performed printing is not normally completed. On the other hand, since the printing has not been completed normally, the host controller saves the currently printed data as it is, stops the operation, and waits for a recovery operation by the operator. Note that the recovery work in this case is processed in the same manner as in the case of the above (2).

[0019]

However, in the above-described conventional paper feed control method of the printer, when an abnormality occurs in paper feed, an operator's intervention is always required.
For this reason, when the printer is used as a printer that performs unattended operation or a printer that is installed in a remote place, there is a problem that it takes time to recover the operation of the printer.

The present invention has been made in view of the above-mentioned problems, and has as its object to solve the problem when an abnormality occurs in paper feeding.
An object of the present invention is to provide a printer control device and a printer control method suitable for use as an unmanned printer or a printer installed at a remote place so that the printer can be restored without the intervention of an operator as much as possible.

[0021]

According to the present invention, there is provided a paper storage unit for storing single-sheet paper, and the paper is sent from the storage unit to a printing unit to perform printing.
In a printer control device for discharging printed paper to a discharge portion by a paper conveying means, an entrance sensor for detecting suction of paper from the storage portion to the printing portion, and discharging of printed paper from the printing portion to the discharge portion. An outlet sensor for detecting that the sheet is discharged to the unit, an abnormality detecting means for detecting an abnormality in the conveyance of the sheet based on detection outputs of the two sensors, and the sheet conveying means when an abnormality in the conveyance of the sheet is detected Means for driving a predetermined amount of paper remaining in the printing unit to the discharge unit side, and detecting the presence or absence of the paper by the detection output of the entrance sensor and the exit sensor after the discharge processing of the paper,
This is achieved by providing a means for judging that the normal state has been restored when no paper is detected and automatically restarting the printing without displaying a conveyance abnormality.

According to the present invention, there is provided a paper storage unit for storing single-sheet paper, from which the paper is sent to a printing unit to perform printing, and the printed paper is printed. A printer for discharging paper to a discharge unit by a paper conveying means, wherein an entrance sensor for detecting suction of paper from the storage unit to the printing unit and printed paper from the printing unit are discharged to the discharge unit. It is detected from the detection output of the exit sensor to detect whether there is an abnormality in the conveyance of the paper, and when the abnormality in the conveyance of the paper is detected, the paper conveyance unit is driven by a predetermined amount to thereby cause the paper remaining in the printing unit to An operation of discharging to the discharge unit side is performed, and after the discharge processing of the paper is completed, the presence or absence of paper is detected by the detection output of the entrance sensor and the exit sensor, and when it is detected that there is no paper, it is determined that the normal state has been restored. It is achieved as to resume the automatic printing without transport failure display.

[0023]

According to this, when a sheet conveyance abnormality is detected, the sheet conveyance means is driven by a predetermined amount to discharge the sheet remaining in the printing section to the discharge section, and after the discharge operation is completed, the sheet conveyance is performed. When it is detected that the error has been recovered, printing is restarted.When a jam occurs, all the operations are stopped and operator intervention is required compared to the conventional case where the operator is required to recover. Can be reduced.
This makes it possible to use the printer as an unattended printer or a printer installed at a remote place.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flowchart showing an example of a paper feed control method for a printer according to the present invention. In particular, FIG. 1 shows an operation for detecting and processing an abnormal paper feed when it occurs. In practicing the present invention, the mechanical structure may use the structure shown in FIG. 2, and the print control circuit may use the print control circuit shown in FIG. Not something. The major difference between the printer of the present invention and the conventional printer lies in a method of detecting and processing an abnormality in paper feeding, which is incorporated in the print control unit 1 in advance. Processing on a program that is Therefore, except for the configuration of the program, it may be the same as the mechanism, circuit configuration, and time chart shown in FIGS. 2 to 4. Therefore, in the embodiment of the present invention, for the sake of simplicity, a description will be given assuming that the same mechanical structure and print control circuit configuration as those of the conventional printer shown in FIGS. 2 to 4 are used. Therefore,
In the following description, the components described with reference numerals corresponding to those shown in FIGS. 2 to 4 are assumed to refer to the members shown in FIGS.

More specifically, the difference between the printer of the present invention and the conventional printer is that the paper 30 of the printing unit is detected when the conveyance error of the paper 30 described in the prior art is detected. + Extra length), the paper sensor 30 is supplied to the entrance sensor 6 and the exit sensor 7.
If there is no, a process is added in which printing is restarted from the beginning without stopping printing.

The specific operation will be described below, taking as an example the case of a double feed in which the sheets 30 are overlapped and attached by half. First, the same operation as in the conventional method is performed until the multi-fed paper 30 is discharged to the stacker 32. That is, when the multi-fed is detected, the motor 3 for the development / transfer process and the paper feed motor 5 are driven by the length of the paper 30. (Step S21). Also, the host controller continues to be notified that the currently performed printing is not normally completed. On the other hand, since printing has not been completed normally, the host controller saves the currently printed data as it is, stops, and waits for the next request. Next, the print control unit 1
The state of the entrance sensor 6 and the exit sensor 7 is checked (step S22). If the outputs of these two sensors 6 and 7 are both off, the paper 30 does not exist in the section from the registration roller 34 to the fixing roller 22, and the multi-fed paper 30 has been normally discharged. Is determined (step S23). Then, the printing control unit 1 proceeds to step S24, starts again from the operation of taking out the paper 30 from the cassette 31, and requests the upper-level control for print data that did not end normally due to the previous occurrence of jam and starts reprinting. I do. That is, the print control unit 1 first releases the abnormal termination of the printing notified at the time of the previous printing to the host controller side, and sends a status indicating that the printing is possible. When the host controller inputs the printable state from the print control unit 1, the previous print data held at the time of inputting the abnormal end status is sent to the print control unit 1 again, and the print that the previous print could not be completed normally is returned. The data will be printed again. Thereafter, the normal state is continued, and the display is restored without displaying the alarm state on the display unit. Therefore, in addition to the double feeding of the paper 30, for example, when one sheet of a size different from the specified size is erroneously inserted, the printer does not stop and discharges the paper 30 to perform the printing operation again. The stop time due to a sheet error in work can be reduced.

On the other hand, when double feed is detected,
It is assumed that when the developing / transfer process motor 3 and the paper feed motor 5 are driven by the length of 0 (step S21), the fixing roller 22 does not rotate due to some other factor. As an example of this, it is conceivable that the rotational load suddenly increases due to the entry of foreign matter into the fixing roller 22, or the developing / transfer process motor 3 loses synchronism due to locking. In such a case, even if the developing / transfer process motor 3 is driven for a predetermined time to discharge the jammed paper 30 in the printing unit 40, the paper 30 is only fed by the pressure roller 35 and the registration roller 34, After the occurrence of a jam, it does not go outside the fixing roller 22 and the backup roller 36. Therefore, after driving for the specified time, the state of the entrance sensor 6 and the exit sensor 7 is checked by the print control unit 1 (step S2).
2), the output of the entrance sensor 6 is turned off, the output of the exit sensor 7 is turned on, and it is detected that the sheet remains at the exit sensor 7 (step S23). That is, this indicates that the discharging operation was not performed normally, and it is determined that the paper 30 still remains in the printing unit 40. For this reason, the print control unit 1 stops displaying the printer after displaying a recommendation to the operator on a display unit (not shown) (step S25), and thereafter waits for a recovery operation by the operator.

The recovery performed by the operator is performed as follows. First, since the display is a jam display of the printing unit, the operator opens the cover (not shown) and opens the printing unit 4.
The presence or absence of the paper 30 in the area 0 is checked, and if there is the paper 30, the cover is closed and the cover is closed. A switch mechanism (not shown) is mounted so that a reset signal is output to the print control unit 1 when the cover of the printer is opened, and the print control unit 1 performs the initial operation again by closing the cover. In the initial operation, it is checked whether or not the entrance sensor 6 and the exit sensor 7 are off.
And heat treatment to a temperature at which the fixing roller 22 can print. When the preliminary operation for enabling these printings is completed and completed, the status indicating that the printing is possible is sent to the host controller. That is, the jam release by the operator is completed in this state. When the host controller inputs the printable state from the print control unit 1, the print data that was not normally ended due to the previous jam occurrence is sent to the print control unit 1 again and the print data cannot be printed by the jam. And print the data again.

In the above-described embodiment, an electrophotographic printer as a non-impact printer has been described as an example. However, the present invention is not limited to this, and a non-impact printer such as a facsimile or an impact printer may be used. And can be applied.

[0030]

As described above, according to the present invention, when a sheet conveyance error (jam) occurs, the sheet is detected by the inlet sensor and the outlet sensor, and the sheet remaining in the printing section is discharged. The presence of paper is detected by the exit sensor, and when it is detected that paper is not present, it is determined that the printer has returned to the normal state, and printing can be automatically resumed without displaying a conveyance error, so a jam occurrence display is displayed. Only when the paper cannot be ejected due to the paper ejection operation and it cannot be restored to the normal state, otherwise it can be judged that the paper has been restored to the normal state and printing can be resumed automatically. Can be minimized. In addition, since the jam can be eliminated and printing can be automatically resumed, it is not necessary to stop printing and wait for a recovery operation by an operator every time a jam occurs, so that the print stop time due to the jam can be reduced as much as possible. Further, the above effects can be expected such that the printer can be effectively used and used as an unmanned printer or a printer installed at a remote place.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention.

FIG. 2 is a schematic structural layout diagram of a paper transport unit in a conventional printer.

FIG. 3 is a block diagram of a print control circuit in a conventional printer.

FIG. 4 is a time chart of a paper transport unit in a conventional printer.

FIG. 5 is a flowchart illustrating an example in which a conventional printer handles a paper feed error.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print control part 3 Motor for development / transfer process 5 Paper feed motor 6 Inlet sensor 7 Outlet sensor 30 Paper 31 Cassette (paper storage part) 32 Stacker (discharge part) 33 Hopping roller 40 Printing part

Claims (4)

(57) [Claims] A printer that has a paper storage unit for storing single-sheet paper, sends the paper from the storage unit to a printing unit, performs printing, and discharges the printed paper to a discharge unit by a paper conveyance unit. The control device according to claim 1, further comprising: an entrance sensor that detects suction of paper from the storage unit to the printing unit; and an exit sensor that detects that printed paper is discharged from the printing unit to the discharge unit. Abnormality detecting means for detecting an abnormality in the conveyance of the sheet based on detection outputs of the two sensors; and, when an abnormality in the conveyance of the sheet is detected, driving the sheet conveying means by a predetermined amount to discharge the sheet remaining in the printing section. Means for ejecting the sheet to the unit side, and detecting the presence or absence of a sheet based on the detection output of the entrance sensor and the exit sensor after the sheet ejection processing. Means for automatically resuming printing without constantly displaying the information. 2. The control device according to claim 1, wherein an electrophotographic printer is used as the printer. 3. A printer having a paper storage unit for storing single-sheet paper, sending the paper from the storage unit to a printing unit, performing printing, and discharging the printed paper to a discharge unit by a paper transport unit. The control device according to claim 1, further comprising: an entrance sensor that detects suction of paper from the storage unit to the printing unit; and an exit sensor that detects that printed paper is discharged from the printing unit to the discharge unit. Abnormality detecting means for detecting an abnormality in the conveyance of the sheet based on detection outputs of the two sensors; and, when an abnormality in the conveyance of the sheet is detected, driving the sheet conveying means by a predetermined amount to discharge the sheet remaining in the printing section. Means for discharging the sheet to the copy unit, and when the sheet conveyance abnormality is detected, continuously notifies the upper controller that the printing is not normally completed, and prints the print data as it is on the upper controller side. Means for requesting storage, and detecting the presence or absence of a sheet by the detection output of the entrance sensor and the exit sensor after the sheet ejection processing, and when it is detected that there is no sheet, the normal state is restored. A printer for determining the conveyance of a new sheet and requesting the print data stored on the upper controller side and automatically resuming printing without displaying a conveyance abnormality. Control device. 4. A printer having a paper storage unit for storing single-sheet paper, sending out the paper from the storage unit to a printing unit, performing printing, and discharging the printed paper to a discharge unit by a paper conveying unit. The control method according to claim 1, wherein an entrance sensor for detecting suction of paper from the storage unit to the printing unit and a detection output of an exit sensor for detecting that printed paper is discharged from the printing unit to the discharge unit. Detecting whether or not there is a sheet conveyance error, performing an operation of driving the sheet conveyance unit by a predetermined amount and discharging the sheet remaining in the printing unit to the discharge unit side when the sheet conveyance error is detected, After the paper discharging process is completed, the presence / absence of the paper is detected based on the detection output of the entrance sensor and the exit sensor, and when the absence of the paper is detected, it is determined that the normal state has been restored, and the conveyance automatically is displayed without displaying the conveyance abnormality. A printer control method characterized by restarting printing.