JP3212154B2 - Printer transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer transport device, and more particularly, to a printer and a copying machine which are fed from a feeding unit based on an image recording signal or a command from an external host device. The present invention relates to a printer transport apparatus in which a recording image is formed on a recording sheet and the recording sheet is discharged to the outside by a transport system.

[0002]

2. Description of the Related Art Conventionally, in a transport device of this type of printer, a sheet feeding means for pressing a predetermined pressure against an upper surface of a recording sheet stacked on a sheet stacking plate and feeding only the uppermost sheet by a frictional force; A sheet surface detection sensor for detecting the height of the upper surface of the stacked recording sheets, a lifter for lifting up the sheet stacking plate, and a sheet feeder for feeding the recording sheets as required by the apparatus; Feed control means for controlling the feeding means, and sheet height for controlling the lifter based on information from the sheet surface detection sensor so that the height of the upper surface of the sheet, which decreases with consumption of the recording sheet, is kept within a certain range. The sheet feeding means is normally separated from the sheet upper surface by the sheet feeding control means, and is controlled so that the sheet feeding means is pressed against the sheet upper surface only during sheet feeding. That.

Further, in a conventional printer, at least one or more recording sheets in addition to a recording sheet being recorded are conveyed or held on a conveyance path other than the discharge conveyance path in the apparatus or a standby portion. In the transport system of such a printer, when it is necessary to interrupt recording, such as when an error occurs during sheet feeding or recording operation, unconditionally remove only the relevant recording sheet outside the machine. The sheet is automatically ejected, or all the recording sheets in the apparatus are automatically ejected outside the apparatus.

[0004]

By the way, in the conventional example, the height of the upper surface of the sheet is changed between the normal state in which the sheet feeding means is separated from the upper surface of the sheet and the time of feeding when the feeding means is pressed against the upper surface of the sheet material. Therefore, the correction operation by the sheet height correction unit can be performed only at the time of sheet feeding where information from the sheet surface detection sensor can be obtained as information of the sheet height at the time of sheet feeding. That is, the check of the sheet height based on the information from the sheet surface detection sensor and the operation of correcting the height of the upper surface of the sheet must be performed within the time when the sheet feeding means is pressed against the upper surface of the sheet. Since the feeding means presses the upper surface of the sheet only for a very short time only when feeding the sheet, it is necessary to check and correct the height of the upper surface of the sheet within the limited short time.

However, since much chattering enters the information of the sheet surface detection sensor and the influence becomes larger due to the sheet conveyance operation especially during the feeding operation, the height of the sheet upper surface must be checked in a short time. It is difficult to perform the correction operation accurately, and a lifter mechanism that operates at high speed is required to perform the correction operation in a short time.

On the other hand, in order to avoid such difficulties, if the checking of the height of the upper surface of the sheet and the correcting operation are not performed at one time but are performed in several steps, the content of control by the correcting means becomes complicated. I will.

Further, in the conventional example in which a sheet other than the sheet being recorded is kept on standby and held in the middle of the transport system, the operation when the recording needs to be interrupted or the like is constant regardless of the conditions. Such a problem arises.

When all sheets in the apparatus are unconditionally discharged, all other reusable sheets in the apparatus are discharged even when recording can be continued by automatically discharging only the sheet in question. Such a discharged sheet is wasted, and the control load is increased, for example, by causing the external host device to repeatedly supply the same print data.

Further, when only the problematic sheet is unconditionally discharged, even if the discharge of one sheet affects other in-machine sheets, the other in-machine sheet is left. Is performed under the control of the external host device, so that the control burden increases. Alternatively, in a case where the influence on another recording sheet due to the ejection of one sheet is not known from the external host device, the recording is continued by the external host device ignoring the influence (for example, one sheet is ejected). As a result, the page order of other recording sheets existing in the apparatus may be changed).

A first object of the present invention is to raise the sheet feeding means while the printing operation of the printer is prohibited so that the sheet feeding means does not hinder the work during the printing operation being prohibited, It is an object of the present invention to provide a printer transport device which enables a normal feeding operation by the sheet feeding means during the printing operation.

A second object of the present invention is to automatically discharge according to the conditions relating to conveyance when it is determined that automatic discharge is necessary based on a diagnosis as to whether or not the printer is functionally operable. It is an object of the present invention to provide a printer transport device capable of performing the above.

[0012]

In order to achieve the first object, a first mode of the present invention is to press-contact a recording sheet stacked on a stacking plate held vertically by a lifter. A sheet surface for detecting a feeding height of an upper surface of the recording sheet in a printer having a sheet feeding unit capable of feeding the recording sheet to the image forming unit one by one by the frictional force. Height detection means, sheet surface correction means for correcting the feed height via the lifter based on a detection signal from the sheet surface height detection means,
The sheet feeding means is controlled in accordance with the printing operation of the printer, and the sheet feeding means is controlled to be pulled up from the upper surface of the recording sheet when the printing operation of the printer is prohibited. And a possible transmission control means.

According to a second aspect of the present invention, which is capable of achieving the second object, a standby portion or a transport path capable of holding at least one or more recording sheets other than the sheet being recorded is provided as an external discharge transport path. In a transport device of a printer capable of automatically discharging the recording sheet including the recording sheet to the outside of the printer, a storage unit for storing conditions related to transport, and at least a transport function of the printer Diagnosing means for diagnosing a functional state; automatic discharging necessity determining means for determining the necessity of the automatic discharge based on information from the diagnostic means; and Automatic discharge control means for controlling the execution of the automatic discharge based on the conditions relating to the conveyance stored in the storage means.

[0014]

According to the first aspect of the present invention, the sheet feeding means is pressed against the upper surface of the sheet during the recording operation regardless of whether or not the sheet is being fed. In the state where the recording of the sheet is prohibited, the sheet feeding means is controlled so as to be pulled up from the upper surface of the sheet, so that the detection of the sheet surface height and the correcting operation thereof can always be accurately performed in the state at the time of sheet feeding. This makes it possible to change the sheet feeding means to a position where it is not obstructed when recording is prohibited such as during sheet feeding or jam clearance.

According to a second aspect of the present invention, a page printer capable of conveying or holding at least one or more recording sheets in addition to a recording sheet being recorded on a conveyance path other than a discharge conveyance path in the apparatus or a standby unit. In the case where it is determined by the automatic ejection necessity determining means that it is necessary to automatically eject the recording sheet in the apparatus, it is controlled so as to automatically eject the recording sheet based on the condition in which the automatic ejection is required or the transport status. If it is necessary to automatically discharge the sheet, it enables the automatic discharge of the in-machine sheet optimally, eliminating waste of the sheet,
Control can be performed so as not to generate unnecessary in-machine residual sheets.

[0016]

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

(First Embodiment First Embodiment) FIG. 2 shows the configuration of a laser beam printer 1 having a feeding means to which the first embodiment of the present invention is applied. That is, the laser beam printer 1 includes a feeding device 4 for feeding the recording sheets S from the cassette 2 storing the recording sheets S to the main body image forming unit 3 as shown in FIG. This feeding device 4
Are a pickup roller 5 as a feeding means for picking up the recording sheet S, a feed roller 6 for sending out the picked-up recording sheet to the main body image forming section 2, a lifter 8 for raising the cassette middle plate 7, and a sheet. Sheet surface detection sensor 9 for detecting the surface height, sheet presence detection sensor 10 for detecting the presence or absence of sheets in cassette 2, cassette presence detection sensor 11 for detecting whether cassette 2 is set, etc. Consists of The feeding device 4 will be described later in detail.

A registration roller pair 12 for synchronously transporting the recording sheet S is disposed downstream of the feed roller 6, and a pre-registration sensor 13 for detecting the transport sheet is disposed immediately before the registration roller pair 12. ing. Also,
Downstream of the registration roller pair 12, the laser scanner unit 1
An image forming unit 3 for forming an image with the laser light from the laser light 4 is provided. Reference numeral 15 denotes a fixing device (fixing roller) provided downstream of the image forming unit 3, and a discharge tray 16 is provided downstream of the fixing device 14 after some transport rollers. Here, the pickup roller 5 and the feed roller 6 are driven by a feeding motor described later, and the other transport system and the lifter 8 are driven by a main motor (not shown).

An external host device 22 is connected via an interface unit 21 to a main control unit 20 for controlling the entire laser beam printer 1.

FIGS. 3A and 3B show the feeding device 4.
The details are shown below.

When the recording sheet S is fed from the cassette 2 to the main body of the recording sheet S, the pickup roller 5 is pressed against the sheet surface at a predetermined pressure and rotated, so that the feed roller 6 is rotated.
The recording sheet S is conveyed to the position. The pickup roller 5 can be moved up and down by a pickup cam mechanism described later. Also, the pickup roller 5
The feed roller 6 is rotated by a drive motor described later. The feed roller 6 receives the recording sheet S from the pickup roller 5 and sends the recording sheet S to the main body image forming unit 3. At this time, if the height of the stacked recording sheets S is lower than the front end 2A of the cassette 2, the pickup cannot be performed. Therefore, the sheet height is checked by the sheet surface detection sensor 9, and the sheet surface is raised by the lifter 8. Is done. Note that, when the cassette 2 is pulled out from the feeding device 4, the lifter 8 is lowered to the home position before ascending. One sensor 9 rotates the arms 9A and 9B according to the height of the sheet surface. When the sheet surface is just at a height at which the sheet can be fed, the light interrupting plate 9D attached to the tip of the arm 9B causes the photo interrupter 9C to be in a light-shielding state, and an "ON" signal is output.

On the other hand, when the height is such that the sheet cannot be fed, the photointerrupter 9C is in a transparent state, and an "OFF" signal is output. Although not shown, the sheet presence / absence detection sensor 10 and the pre-registration sensor 13 have the same mechanism. The cassette presence detection sensor 11 is provided with a frame 1 attached to the cassette 2 as shown in FIG.
1K and push button switches 11A, 11B, 1 on the main body side
1C, the presence or absence of the cassette 2 is determined by the on / off of these push button switches, and the combination of the three switches on / off of the sheet S contained in the cassette 2 is determined. The size can be determined.

FIG. 1 is a block diagram showing a configuration according to the first embodiment of the present invention. The laser beam printer 1 according to the first embodiment of the present invention is controlled by a printer main control unit 20 including a CPU, a ROM, a RAM, a gate element, and the like. The apparatus further includes a self-diagnosis unit 30, a state management unit 31, a recording and conveyance control unit 32, and a feeding device control unit 33 for controlling the feeding device 4.

The self-diagnosis means 30 monitors abnormalities (failures, jams, etc.) in the various parts of the laser printer 1 on the basis of information from the various parts, and notifies the state managing means 31 of any abnormalities found. Things. The state management means 31 comprehensively manages the following control means according to the state of the laser beam printer 1 (warming up, printing standby, printing, stop, failure, jam, etc.).

Further, when the recording / transporting control means 32 receives a recording instruction from the external host device 22 via the interface section 21, the recording / transporting control means 33 which will be described later.
And sends the recording sheet S to the image forming unit 3, records a predetermined image on the recording sheet based on the image information sent from the external host device 22, and conveys the sheet until it is discharged to the discharge tray 16. Control. At this time, the input circuit 3
The sheet presence / absence detection sensor 1 fetched via the 4, 4
0, it is also determined whether or not recording is possible based on information from the cassette presence detection sensor 11 and the like and information from the state management means 31.

The feeding device control means 33 includes a sheet surface height correction means 36 for controlling the height of the recording sheet S so that the recording sheet S can always be fed, and a recording sheet S of the cassette 2 in the image forming section. And a feed control means 37 for controlling the vertical movement of the pick-up roller 5, and the pick-up roller 5 and the feed roller 6. Feed control means 3 for feeding the recording sheet S
9.

Also, the signal from the sheet surface detection sensor 9 is taken into the sheet surface height correction means 36 via the input circuit 40 so that the lifter 8 is driven via the lifter driving means 41. The signal from the sensor 9 is monitored, and when the signal from the sensor 9 is turned "off" (read several times to prevent chattering), it is determined that correction is necessary. When it is determined that the correction is necessary, the lifter 8 is raised by the lifter driving means 41 until the signal from the sensor 9 is turned “ON”.

The pickup cam mechanism 42 includes a cam (not shown) for moving the pickup roller 5 up and down, and a solenoid for stopping the cam at a predetermined stop position and releasing the stop. The cam has two stop positions, a state in which the pickup roller 5 is raised and a state in which the pickup roller 5 is lowered on the sheet surface, and the stop is released by the operation of the solenoid. Therefore, the pickup roller control means 38 can drive the pickup roller 5 from the raised position to the lowered position or from the lowered position to the raised position by turning on and off the above-mentioned solenoid. The pickup roller 5 and the feed roller 6 control the driver 4 under the control of the feed / transport control means 39.
3 is driven to rotate by a drive motor 44 driven through the motor 3.

FIG. 4 shows a procedure of a control operation relating to the sheet surface height correcting means 36 of the printer main controller 20. First, in step S1, the process waits until initialization after power-on is completed. Drive means 4 for lifter 8
Since the main motor 1 can be driven in the standby state, the lifter 8 can be raised in the standby state and in the recording state while the main motor is being driven.
Here, the standby state refers to a state in which the fixing device 15 is controlled to the standby temperature and recording can be started immediately by a recording instruction from the external host device 22. The state management means 31 warms up after the initialization, starts the laser beam printer 1 to a standby state, and waits for a recording instruction from the external host device 22. Therefore, if it is confirmed in step S1 that the initialization has been completed, the flow advances to step S2 to determine whether or not the apparatus is in the standby state based on the information from the state management means 31. It is determined whether or not it is in a recordable state. If it is not in a recordable state, the process proceeds to step S7, and the driving of the lifter 8 is prohibited. If it is determined in step S2 that the apparatus is in the standby state or in step S3 that it is in the recordable state, the process proceeds to step S4.

In step S4, the presence / absence of the signal is determined based on a signal from the cassette presence / absence detection sensor 11. If the determination is negative, the process proceeds to step S7, and the driving of the lifter 8 is prohibited. If the determination is affirmative, the process proceeds to step S5. Step S
In 5, it is determined whether or not the predetermined sheet surface height is maintained based on the signal of the sheet surface detection sensor 9. If not, the process proceeds to step S 6 to drive the lifter 8, The lifting of the lifter 8 is continued until the height of the lifter 8 reaches the predetermined height of the sheet surface. When it is determined in step S5 that the height of the lifter 8 has reached the predetermined height, the process proceeds to step S7 to stop the lifter 8. The above control is repeated until the power is turned off.

As described above, the standby state in step S2, or the recordable state in step S3,
If the insertion of the cassette is confirmed in step S4, first, in step S6, the lifter 8 is driven (initial rise) until the sheet surface height reaches a height at which the sheet can be fed, and then recording is performed. As the height of the seat decreases as the distance increases, the height of the seat is corrected (correction rise).
If the standby state or the print state is lost due to the occurrence of a jam or a failure during the initial rise and the correction rise, or if the cassette is pulled out, the process proceeds to step S7 to stop driving the lifter 8. Furthermore,
If it is determined in step S5 that the sheet surface height is insufficient, the driving of the lifter 8 is started in step S6,
At 5, the correction operation is continued while checking whether the sheet surface height has reached a predetermined height. If there is no cassette in step S4, the process proceeds to step S7 to stop the lifter 8. Also, when it is determined in step S5 that the sheet surface height has reached the predetermined height, the lifter 8 is also stopped in step S7, and the correction operation ends.

Here, in the feeding device 4 configured as in the present embodiment, there is a gap between the recording sheets S stacked on the middle plate 7 of the cassette due to undulation or wrinkling of the recording sheets S. . Therefore, when the pickup roller 5 is pressed against the sheet S at a predetermined pressure for feeding, the sheet surface height is reduced. FIG. 5A shows such a state. As shown in the figure, in the case of (A) in which the pickup roller 5 is pressed against the sheet surface and in the case of (B) in which the pickup roller 5 is raised, the height of the latter is higher by h. As described above, the sheet surface height correction means 36 monitors the sheet surface height and controls the correction operation based on the signal from the sheet surface detection sensor 9, but as in the conventional case, the pickup roller 5 is lowered only at the time of feeding. In this case, as shown in FIG. 5A, the sheet surface is lowered during feeding, so that the sheet surface detection signal is in an "off" state. At other times, the sheet surface detection signal is "on". Therefore, if the height of the sheet surface is monitored and corrected regardless of the feeding timing, accurate control cannot be performed. That is, in order for the sheet surface height correcting means 36 to accurately perform the sheet surface correcting operation, the sheet surface check and correction must be performed at the time of feeding and during the time when the pickup roller 5 is pressed against the sheet surface. Regardless of the necessity of performing the operation, since one pick-up time is short, the sheet check and the correcting operation are divided into a plurality of feeding opportunities, or the correcting operation is started before the feeding operation and the correcting operation is started. The control becomes very complicated, for example, only during the final stage during the pickup operation. Conversely, if the pickup roller 5 is always lowered, the cassette 2 may be inserted or removed to supply the recording sheet, or the pickup roller 5 may be operated when a jam occurs during feeding. Hinders

Therefore, in this embodiment, the pickup roller control means 38 receives the information on the state of the laser beam printer 1 from the state management means 31 and always lowers the pickup roller 4 during the recording operation regardless of whether the sheet is being fed. In any other state (for example, when a jam or a failure occurs), control is performed to raise the pickup roller 5.

FIG. 6 shows the procedure of the control operation by the pickup roller control means 38 of this embodiment. The pickup roller control means 38 receives information on the state of the apparatus from the state management means 31 and controls the vertical movement of the pickup roller 5 based on the state. That is, first, S1
In step 1, the process waits until the initialization after power-on is completed. Then, when the initialization is completed, it is determined in S12 whether or not the recording is possible. If the recording is possible, the process proceeds to S13, where the pickup roller 5 is lowered onto the sheet surface. The power supply is turned off for the control operation of raising
Repeat until.

Here, when the recording / transporting control means 32 starts an operation relating to recording in accordance with an instruction from the external host device 22, the state managing means 31 informs the pickup roller control means 38 that recording is possible. When the recording is completed, or when the recording is interrupted due to the occurrence of a jam or a failure (detection by the self-diagnosis unit 30), the pickup roller control unit 38 is notified that the recording is not possible. Accordingly, the pickup roller control means 38 lowers the pickup roller 5 on the sheet surface during recording as shown in step S13 according to the judgment in step S12, and the recording is stopped or the recording is prohibited due to a jam or failure. Step S
The pickup roller 5 is raised as shown in FIG.

According to the above control, the sheet surface height can be checked and corrected in the state shown in FIG. 5A during the recordable state, and the pickup roller 5 is moved when a jam occurs. It can be pulled out to the position shown in FIG.

(First Embodiment Second Embodiment) In the first embodiment of the first embodiment, the pickup roller 5 is lowered onto the sheet surface only in the recordable state. However, in the present embodiment, the same applies to the standby state. The pickup roller 5 is lowered onto the sheet surface.
In the standby state or the recordable state, the initial rise is performed when it is first confirmed that a cassette is present. In this case, the lifter 8 is also operated based on the signal from the sheet surface detection sensor 9.
The pickup roller 5 in the standby state.
Is in the raised position, the state shown in FIG. 5B is obtained, and it cannot be adjusted to the optimum sheet surface height in the state at the time of feeding. Therefore, by setting the pickup roller 5 at the lowered position even during standby for initial raising, the sheet surface height at the time of feeding can be adjusted to an optimum state.

FIG. 7 shows an operation procedure of the pickup roller control means 38 according to this embodiment. First, as in the case of the first embodiment, in step S21, the process waits until the initialization after the power is turned on is completed, and in step S22, it is determined whether the apparatus is in a standby state. If it is not in the standby state, the process proceeds to step S23, and it is determined whether or not it is in the recordable state. If the recording is not possible, the process proceeds to step S25, and the pickup roller 5 is raised. On the other hand, if it is determined in step S22 that the apparatus is in the standby state, and if it is determined in step S23 that the apparatus is in the recordable state, the process proceeds to step S24 to lower the pickup roller 5 on the sheet surface. Continue until ".

With the above-described control, the sheet surface height correction control can be accurately performed during standby or during recording.

(First Embodiment Third Embodiment) In the first embodiment and the second embodiment of the first embodiment, the pickup roller 5 is controlled to always drop on the sheet surface in the recordable state and the standby state. However, in the present embodiment, when there is no sheet or no cassette, control is performed so that the pickup roller 5 is raised even in the standby state or the recordable state. That is, the operator may insert or remove the cassette 2 during standby or during recording preparation. In this case, it is obstructive if the pickup roller 5 is lowered. On the other hand, when there is no sheet even when there is a cassette, it is expected that the cassette 2 will be pulled in and out to replenish sheets. Conversely, when there is no sheet, the difference in sheet surface height as shown in FIG. Therefore, there is no need to set the pickup roller 5 to the lower position. Therefore, even in the recordable state or the standby state, when there is no cassette or no sheet, by immediately raising the pickup roller 5, the printer can be more easily used.

FIG. 8 shows the configuration of the third embodiment of the first embodiment. The configuration of this embodiment is almost the same as that of FIG. 1 except that signals are taken in from the sheet presence / absence detection sensor 10 and the cassette presence / absence detection sensor 11 to the pickup roller control means 38 via the input circuits 34 and 35. The pick-up roller control means 38 controls the pick-up roller 5 based on this signal.

FIG. 9 shows an operation procedure of the pickup roller control means 37 according to this embodiment. Steps S31 to S3
Steps S3 to S3 are the same as steps S21 to S23 of the second embodiment, but if the standby state is set in step S32 or the recordable state is set in step S33, the cassette presence / absence detection sensor 11 determines in step S34. Is monitored to determine the presence or absence of the cassette. If there is no cassette, the process proceeds to step S37 to raise the pickup roller 5. If a cassette is present in step S34, the process proceeds to step S35 to further monitor the signal from the sheet presence / absence detection sensor 10 to determine whether there is a sheet. And if there is no sheet,
Proceeding to step S37, the pickup roller 5 is raised. That is, when there is no cassette or no sheet, the pickup roller 5 is raised even in the standby state and in the recordable state. If there is a sheet in step S35, step S36 is performed. To lower the pickup roller 5 on the sheet surface.

When the cassette 2 is attached or detached due to sheet exhaustion or the like under the above configuration and control, the pickup roller 5 can be raised so as not to be in the way.

Next, each embodiment according to the second embodiment of the present invention will be described with reference to FIGS.

FIG. 11 shows an example of the configuration of the laser beam printer 1 according to the second embodiment. The laser beam printer 1 of this embodiment includes an upper cassette 2U and a lower cassette 2D. 5U and 6U are pickup rollers and feed rollers for the upper cassette 2U, 5D and 6U.
D is a pickup roller and a feed roller for the lower cassette 2D. Reference numeral 51 denotes a fixing detection sensor disposed immediately after the fixing device 15, and reference numeral 52 denotes a transport roller 53 provided downstream of the sensor 51. Double-sided flapper 53
Is a flapper that divides the recording sheet into a double-sided conveyance mechanism and a conveyance path to a discharge port, which will be described later. The recording sheet is driven by the double-sided flapper solenoid 53A to the double-sided conveyance mechanism side, and when the recording sheet is “off”, the discharge side is set. Sent to The transport roller 5 is located downstream of the transport path on the discharge port side of the double-sided flapper 53.
The FU (face-up) flapper 55 is disposed downstream of the roller 54. The FU flapper 55 is connected to the FD (face down) discharge port 56 and the FU
This is a flapper that divides the recording sheet into a conveyance path to two discharge ports with the discharge port 57. The recording sheet is discharged to the FU side by driving the FU flapper solenoid 58, and is discharged to the FD side when the recording sheet is turned off. . In addition, F of the flapper 55
An FD discharge port 56 is provided on the downstream side of the D side, and a discharge roller 59 and a discharge port sensor 60 are disposed in the FD discharge port 56 so that a recording sheet is discharged to the FD tray 16.

The double-sided conveying mechanism is a mechanism for reversing the recording sheet on which single-side recording has been performed for double-sided printing and feeding the recording sheet to the registration roller pair 12 again. The double-sided rollers 61 and 62, the double-sided detection sensor 63, the reversing roller 64, a resupply roller 65, a resupply detection sensor 66, and the like. That is, two-sided rollers 61 and 62 are disposed downstream of the two-sided flapper 53 on the two-sided conveyance mechanism side, and a two-sided detection for detecting whether or not a sheet has been fed between the two-sided rollers 61 and 62. A sensor 63 is provided. Further, a reversing roller 64 is provided downstream of the two-sided roller 62, and the recording sheet sent from the two-sided flapper 53 is conveyed to the reversing roller 64 by the two-sided rollers 61 and 62. The reversing roller 64 is a double-sided detection sensor 63
From the trailing edge detection (when paper is detected and then there is no paper), the motor rotates forward one rotation (in the direction of arrow a in the figure) at a predetermined timing, and then reverses three rotations (in the figure) Arrow b). The sheet thus sent is conveyed while changing its direction, and is conveyed to a re-feeding port 7 at a branch point 70 in the figure.
Branched to 1. A re-supply roller 65 and a re-supply detection sensor 66 are provided on the transport path 71 on the downstream side of the reversing roller 64.
2 are provided. Then, the recording sheet is guided by the reversing roller 64 to the resupply roller 65 via the branch point 70, and is fed by the resupply roller 65 to a position where the leading end of the recording sheet has advanced a predetermined distance from the refeed detection sensor 66.

On the other hand, the laser beam printer 1 has a main control unit 80 as shown in FIG.
0 is connected to an external host device 22 via an interface unit 21. The main controller 80 includes a microprocessor for controlling the entire apparatus, a ROM for storing a control program, a RAM for storing data and the like, a gate element, and the like. The main control unit 8
The input / output port 0 includes a main motor drive circuit 82 for a main motor 81 that drives each transport mechanism downstream of the registration roller pair 12, an image forming unit control circuit 83 for controlling the image forming unit 3, A laser control circuit 84 for controlling the laser scanner section 14, and the fixing roller 15
A fixing device control circuit 85 for controlling a halogen heater (not shown) incorporated in the printer at a predetermined temperature is connected to each of the input ports.
The resupply sensors 13, 51, 60, 63, 66 detect the sizes of the recording sheets stored in the upper and lower cassettes 2U, 2D via the input circuits 86, 87, 88, 89, 90, respectively. Upper and lower cassette size detection sensors 91 and 92 are connected via input circuits 93 and 94, respectively.
Further, the output port includes the pickup roller 5.
A pickup solenoid 95 for turning on and off a cam mechanism (not shown) for vertically moving U and 5D is provided via a driver 96, and a feed motor 97 for driving the pickup rollers 5U and 5D and the feed rollers 6U and 6D. Through the feed motor drive circuit 98, and
A registration roller solenoid 99 for turning on / off the driving of the registration roller pair 12 is driven by a driver 100 to drive a double-sided flapper 53 via a double-sided flapper solenoid 53.
A drives the FU flapper 55 via the driver 101, the FU flapper solenoid 58 drives the double-sided rollers 61 and 62 via the driver 102, and the double-sided roller clutch 103 drives the reverse roller 64 via the driver 104. The motor 105 is a reverse motor drive circuit 106
Connected to each other.

The interface unit 21 is provided with an RDY signal for notifying that the main control unit 80 is in a printable state to the external host device 22.
Reference numeral 2 denotes a PRNT signal for instructing the main control unit 80 to start printing, a VSREQ signal for requesting the external host device 22 to output a vertical synchronizing signal VSYNC for image output (sub-scanning direction), and an image. The synchronization signal VSYNC in the vertical direction (sub-scanning direction) of the output, the synchronization signal BD in the horizontal direction (main scanning direction) of the image output output from the main control unit 43 to the external device 3, and the external host device 22
An image signal VDO for transmitting a dot image serially in synchronization with the NC signal and the BD signal is transmitted, and a handshake type serial communication line I
The external host device 22 transmits various commands (designation of a paper feed port, etc.) to the main control unit 80 through the serial communication line I / F, and the external host device 22 , Various kinds of information (such as failure information) relating to the state of the laser beam printer 1 can be transmitted.

Reference numeral 110 in the figure denotes a low-voltage power supply unit that converts a commercial AC voltage into a predetermined DC voltage.

With the above configuration, when the laser beam printer 1 receives a recording instruction (PRNT signal) from the external host device 22, the transmission port (upper stage) previously specified by the external host device 22 by the serial communication I / F. A recording sheet is fed from a cassette, a lower cassette, a double-sided resupply port, and the like. After forming an image on the recording sheet in accordance with a predetermined electrophotographic process, a destination (FD discharge port, FU discharge port) similarly designated in advance. , A double-sided conveying mechanism, etc.).

That is, when performing double-sided recording, the external host device 22 first specifies the feeding port to either the upper cassette 2U or the lower cassette 2D by the serial communication I / F, and further sets the destination to the double-sided resupply port. Specify and transmit the PRNT signal. As a result, the laser beam printer 1 feeds the recording sheet from the designated one of the upper and lower cassettes and conveys the recording sheet to the image forming unit 3. Further, by transmitting a VDO signal to the laser beam printer 1 at a predetermined timing from the external host device 22, a predetermined image can be recorded on one side of the recording sheet. Thus, in the laser beam printer 1, after the recording sheet on which the image formation is completed is fixed by the fixing roller 15, the double-sided flapper 53 is fixed.
To drive the recording sheet to the double-sided conveyance mechanism. The recording sheet sent to the two-sided conveyance mechanism is sent to the reversing roller 64 by the two-sided rollers 61 and 62, where the recording sheet is reversed by the reversing roller 64, and then the re-supply roller 65 via the branch point 70.
The sheet is further conveyed from the re-supply sensor 66 to a predetermined position by the re-supply roller 65, and enters a re-supply standby state (hereinafter, this position is referred to as a double-sided re-supply opening). At a predetermined timing shortly before the re-supply standby state, a re-supply enable flag described later is set, and the serial communication I / O
Since this state is transmitted to the external host device 22 by F, the external host device 22 confirms that the recording sheet sent to the double-sided conveyance mechanism can be resupplied by the flag. Also, if the external host device is a serial communication I / F
To the double-sided resupply and the destination to FU or F
When the PRNT signal is output after designation to the D discharge port, and the laser beam printer 1 is instructed to record the second side,
In the laser beam printer 1, after the leading end of the recording sheet is conveyed to the position of the registration roller pair 12, recording is performed on the second side in the same sequence as the first side, and then the recording sheet is discharged from the designated discharge port.

The operation described above is for double-sided recording on one recording sheet. In the laser beam printer 1 according to the second embodiment of the present invention, up to two recording sheets can be made to stand by in the double-sided conveying mechanism. . That is, with one recording sheet in the double-sided conveyance mechanism, another recording sheet designated for the double-sided conveyance mechanism is fed from one of the cassettes for recording, or the double-sided conveyance mechanism has two recording sheets. In this state, it is possible to feed and record a recording sheet from the cassette to the FU or FD discharge port. Normally, when continuous printing is performed in double-sided printing, since the processing capability is reduced if both sides are printed one by one as described above, the external host device 22 continuously prints the first two sheets from one of the cassettes. After the sheet is fed to the double-sided conveyance mechanism, one sheet is fed from the double-sided resupply port to the discharge port, and then the control of feeding one sheet from the cassette to the double-sided conveyance mechanism is repeated. Performs alternate feeding control. That is, in the order of pages to be recorded, 1,
Recording is performed in the order of 3, 2, 5, 4, 7, 6, 9, 8,. With this control, another recording sheet that is waiting for double-sided re-feeding can be recorded in the time required for the recording sheet fed from the cassette and having been subjected to single-sided recording to be ready for double-sided re-feeding. Can be reduced.

Here, if any error occurs in the apparatus during continuous double-sided printing due to the alternate feed control as described above, the laser beam printer 1 of this embodiment uses the sheet being recorded. The manner in which the recording sheet in the apparatus is automatically discharged can be changed depending on the feeding mode.

FIG. 10 shows the configuration of functions related to automatic sheet ejection control according to the second embodiment of the present invention. In the laser beam printer 1 of this embodiment, the main control unit 80 includes a transport control unit 201, a self-diagnosis unit 202, and an external device communication unit 20.
3. Automatic discharge necessity determining means 204, transport information storage means 2
The transport control unit 201 further includes a transport operation control unit 206 and an automatic discharge control unit 207, and the sheet transport information storage unit 205 includes
08, destination storage means 209, in-flight seat counter 21
0, a rechargeable flag 211, an automatic discharging flag 212, and the like.

The external device communication means 203 exchanges information between the laser beam printer 1 and the external host device 22 through each signal of the interface section 21 and serial communication.

The conveyance control means 201 feeds a recording sheet,
It controls each transport operation of transport, double-sided reverse transport, and discharge. The transfer operation control unit 206 of the transfer control unit 201 stores a recording instruction signal obtained from the host device 22 via the external device communication unit 203, an automatic discharge instruction from the automatic discharge control unit 207, and the transfer information storage unit 205. The sheet conveyance from the feeding of the recording sheet to the discharge of the recording sheet is controlled in accordance with the received various kinds of conveyance information. On the other hand, the automatic discharge control means 20
7 receives the information indicating that the automatic discharge is necessary from the automatic discharge necessity determining means 204, and executes the transport operation control means 2 according to the situation.
06, an automatic ejection instruction is given, and the recording sheet in the apparatus is automatically ejected. The self-diagnosis unit 202 monitors the operation of each unit in the laser beam printer 1, and detects the occurrence of a failure or the like.

The automatic ejection necessity determining means 204 has a function of judging whether or not the automatic ejection is necessary. When the self-diagnosis means 202 confirms an abnormality in the apparatus, the in-machine sheet of the sheet transport information storage means 205 described later is used. Counter 21
It checks whether there is a recording sheet being conveyed or waiting in the machine by counting from 0, and automatically ejects if an abnormality that occurs while the recording sheet exists in the machine can continue sheet conveyance. Is determined to be necessary, and the information to that effect is supplied to the transport control means 201.

The sheet transport information storage means 205 has a function of storing various information relating to sheet transport. The supply port storage means 208 stores information on the supply port designated by the external host device 22 via the external device communication means 203. The destination storage means 209 similarly stores information on the destination specified by the external host device 22. The in-machine sheet counter 210 counts up by one every time one sheet is sent from the recording sheet sending unit by the conveyance control unit 201 and counts down by one every time a recording sheet is discharged outside the machine. The number is stored.

The refeedable flag 211 is a flag indicating that the recording sheet sent to the double-sided conveyance mechanism is in a state where double-sided refeeding is possible. Is set at a predetermined timing.

The automatic ejection flag 212 is set when the automatic ejection operation is being performed, and is reset when all the recording sheets that need to be automatically ejected are completed.
This indicates that the laser beam printer 1 is performing automatic ejection.

FIG. 13 shows the procedure of the control operation by the transfer operation control means 206. First, in step S101 (hereinafter, steps are simply represented by S), the process waits until the sheet interval with the precedingly conveyed recording sheet is sufficiently maintained. If it is determined that the sheet interval is sufficient, the process proceeds to S102, where it is determined whether an automatic feeding instruction has been issued. Note that the automatic feeding instruction is issued from the automatic discharge control unit 207 as described later.
If the automatic feed instruction is issued in S102, immediately S1
Then, the process proceeds to the feeding operation of Step 05. If the automatic feeding instruction has not been issued in S102, the process proceeds to step S103, and the automatic discharging flag 212 is checked. And automatic discharging flag 2
If 12 has been set, the process returns to S102. That is,
In step S103, processing for not feeding a new recording sheet is performed until the automatic discharge processing is completed. S
If the automatic ejection flag 212 is not set in step 103, the process proceeds to step S104. In step S104, the process waits for the PRNT signal to be output from the external host device 22. PRN
If the T signal is output, in S105, the feed port storage means 2
08 and the designated sheet feeding port of the recording sheet to be fed is not the two-sided re-feeding port.
10 is incremented by one, and the flow proceeds to the feeding operation of S106.

In S106, the recording sheet is fed from the feeding port set in the feeding port storage means 208, and the recording sheet is transported to the registration roller pair 12. When the recording sheet is conveyed to the registration roller pair 12, the automatic ejection flag 212 is checked in S107. If the automatic ejection flag is set, the process proceeds to S110, and if reset, the process proceeds to S108. As will be described later, the automatic ejection control means 207 sets the automatic ejection flag 212 when entering the automatic ejection control state. When the automatic discharge state is reached, the recording sheet being fed is automatically conveyed after the registration roller pair 12 and discharged. If the automatic ejection flag 212 is reset in S107, a VSREQ signal is output in S108 and S10
At 9, wait for the VSYNC signal to be output from the device 22. If the automatic ejection flag 212 is set in S107, or if the VSYNC signal is output in S109, the registration roller pair 12 is driven in S110 to convey the recording sheet from the image forming unit 3 to the fixing roller 15, and A recording flag (not shown) indicating that an image is being formed while the recording sheet is passing through the image forming unit 3 is set.
In S111, the recording sheet is conveyed to the destination specified in the destination storage unit 209. That is, if the destination stored in the destination designation storage means 209 is the FD discharge port, the transport rollers 52 and 54 and the discharge roller 59 are driven as they are, and the recording sheet is discharged to the FD discharge port 56. When the destination is designated by the FU outlet 57, the FU flapper 55 is driven to move the transport path to the FU outlet 57.
And the recording sheet is discharged from the FU discharge port 57. Furthermore, when the destination specification is a double-sided resupply,
By driving the double-sided flapper 33, the conveyance path is switched to the double-sided conveyance mechanism side, the double-sided reverse conveyance is performed as described above, and the recording sheet is conveyed to the double-side refeed standby state. afterwards,
In step S112, if the destination of the sheet specified in the destination storage unit 209 is the FD discharge port 56 or the FU discharge port 57, the count value of the in-machine sheet counter 210 after the discharge is completed is reduced by one.

FIG. 14 shows the procedure of the control operation by the automatic discharge control means 207. First, in step S201, the process waits until the automatic discharge necessity determination unit 204 determines that automatic discharge is necessary. If it is determined that automatic discharge is necessary, the process proceeds to step S202.
After setting the automatic discharge flag 212 in S20,
In step 3, it is determined whether or not the designated feed port for the recording sheet being printed stored in the feed port storage unit 208 is a double-sided re-feed port. Here, if the designated feeding port is a double-sided re-feeding port, the process proceeds to all in-machine sheet discharge control in S204 and below. . Such control is performed for the following reasons.

If any recording error occurs during the recording of the first side in the double-sided recording, only the recording sheet currently being recorded is automatically ejected, and then the recording sheet is re-supplied from a cassette or the like, and the recording sheet is re-started.
Even if printing on the first side is performed, the page order with the recording sheet on which recording on the other first side has been completed (recording paper or the like waiting in the double-sided conveyance mechanism) is not disturbed, so the in-machine recording on the first side has been completed. Other sheets are reusable. However, if a recording error occurs during the recording of the second side, if only the recording sheet currently being recorded is automatically ejected and then the recording sheet is re-supplied from a cassette or the like and the recording of the first side is performed again, Since the page order is out of alignment with the recording sheet on which the recording of the first side has been completed, the other sheets in the machine on which the recording of the first side has been completed cannot be reused. Therefore, in the former case, it is necessary to perform a control of automatically discharging only the recording sheet during recording, and in the latter case, to automatically discharge the sheets in all the apparatuses. First, in S203, if the designated sheet feeding port of the recording sheet being printed is the double-sided re-feeding port, the process proceeds to S204, and the count value of the in-machine sheet counter 210 at that time is transferred to the external host device via the external device communication means 203. Let 22 know. This is because the number of sheets to be re-recorded in the external host device 22 is notified as the number of sheets to be re-recorded to the external host device 22 in order to discharge all the sheets in the apparatus in the subsequent control.
9 to automatically discharge all the in-machine sheets as described above. First, in S205, the information of the destination storage means 209 regarding the fed recording sheet is stored in the FD outlet 5
Change to 6. As a result, all the recording sheets fed so far are discharged to the FD discharge port 56. Next, S
At 206, it is determined whether or not the resupply possible flag 211 is set.
After setting the information of the feeding port storage means 208 relating to the recording sheet to be fed to the double-sided refeeding port in step 7, an automatic feeding instruction is issued to the transport operation control means 206 in S208. If the re-supply possible flag 211 is reset in S206, the flow advances to S209 to determine whether or not the in-machine seat counter 210 is zero.
Proceed to 210. That is, for the in-machine sheet during recording, the FD discharge is designated and the conveyance is continued as it is. For the in-machine sheet being conveyed to the duplex conveying mechanism or in the standby state, the in-machine sheet is immediately re-supplied and fed to the FD. By repeating the discharging operation until the number of in-machine sheets becomes zero, all the in-machine sheets are discharged out of the machine.

If it is determined in step S203 that the designated sheet supply port of the recording sheet being recorded is other than the double-side resupply port, the process proceeds to step S211.
To the external host device 2 via the external device communication means 203 with the number of sheets that need to be re-recorded as one.
Inform 2 This is for automatically discharging only the recording sheet during recording. Subsequently, the information of the destination storage unit 209 regarding the fed recording sheet is changed to the FD discharge port 56 in S212. Thereby, the transport operation control means 20
Reference numeral 6 discharges the recording sheet being recorded or being fed to the FD discharge port 56. After the predetermined automatic ejection control is completed, the process proceeds to S210, and the automatic ejection flag 212 is reset.

FIG. 15 shows the procedure of the control operation by the automatic discharge necessity judging means 204. In S301, the self-diagnosis unit 20
2 determines whether any abnormality has been detected. If it is determined that an abnormality has been detected, the process proceeds to S302.
In step S302, a recording flag indicating that recording is in progress is checked. If recording is in progress, it is determined in step S303 whether transport can be continued. That is, when the generated abnormality is an abnormality related to the transport mechanism of the laser beam printer 1 (a motor failure or the like), it is determined that the transport cannot be continued. If it is determined in S303 that the continuation of the conveyance is possible, the control of the conveyance
An automatic ejection request is issued for 1.

With the above-described control, the order of the pages is prevented from being changed, the waste of the recording sheets is prevented by using the reusable sheets, and the external host device 22 is prevented.
The burden on the user can be reduced.

(Second Embodiment Second Embodiment) The second embodiment of the present invention described above.
In the first embodiment according to the mode, when an abnormality occurs in the machine,
Although the method of automatic discharge is changed depending on the feeding port of the recording sheet during recording, it is also possible to change the method of automatic discharge depending on the conditions when the automatic discharge becomes necessary.

The laser beam printer 1 having the configuration shown in FIGS. 10 to 12 has a function of receiving a recording cancellation from the external host device 22. That is, even after the external host device 22 outputs a recording instruction to the laser beam printer 1 by the PRNT signal, before the completion of the feeding (that is, before the VSREQ signal is output), the PRNT signal falls. The laser beam printer 1 considers that the recording has been canceled, and can automatically discharge the recording sheet being fed out of the apparatus without outputting the VSREQ signal. Therefore, in the present embodiment (second embodiment), similarly to the first embodiment, when the self-diagnosis unit 202 diagnoses the abnormality, the automatic discharge necessity determining unit that determines the necessity of automatically discharging the in-machine sheet is determined. 204 and an automatic discharge control means 207 for controlling automatic discharge.

However, in the laser beam printer 1 according to the second embodiment of the second embodiment described below, the automatic ejection of the in-machine sheet when an abnormality is detected is not divided into cases as in the first embodiment, and is unconditional. Automatically ejects all recording sheets inside the machine to the outside of the machine. This is because, in many cases where an abnormality is detected by the self-diagnosis unit 202, it is impossible to automatically recover from a failure of the image forming unit 3 or a failure of the fixing roller 5, or it is possible to recover automatically. This is because the recording sheet should not be left inside the apparatus as much as possible in such a state.

On the other hand, the laser beam printer according to the second embodiment of the second embodiment has the above-described recording cancel function. Therefore, in the case of automatic ejection by canceling recording, the automatic ejection method is controlled by the feeding port. I changed it. That is, when a recording cancel instruction is issued for the recording sheet fed from the double-sided resupply opening, the page order is changed as described in the first embodiment of the second embodiment. Is automatically discharged, and when a recording cancel instruction is issued for a recording sheet fed from another feeding port, only the recording sheet is discharged.

FIG. 16 shows the procedure of the control operation by the transfer operation control means 206 according to the second embodiment of the second embodiment. Note that S
Steps 401 to S406 are the same as steps S101 to S106 in the flow (FIG. 13) of the first embodiment of the second embodiment. Next, in S407, it is determined whether or not recording has been canceled.
That is, when the feeding is completed, the presence or absence of the PRNT signal is checked before outputting the VSREQ signal, and if there is no printing, it is determined that the recording has been canceled and the process proceeds to S414. Then, in S414, the fact that the recording has been canceled is notified to the automatic ejection control means 207, and the process directly proceeds to the conveyance control in S411 and thereafter. On the other hand, the flow when the recording is not canceled is the same as S408 to S413 and S107 to S112 of the first embodiment of the second embodiment.

FIG. 17 shows a control operation procedure by the automatic discharge control means 207 of the second embodiment of the second embodiment. First, S
In step 501, the automatic discharge necessity determination unit 204 checks whether or not automatic discharge is necessary. If it is determined that automatic discharge is necessary, the process proceeds to step S502. After the automatic discharge flag 212 is set, the process proceeds from step S503 to step S509. The process proceeds to the sheet discharge control in all the machines up to. The control from S503 to S509 is the same as the flow from S204 to S208 shown in FIG. 14 of the first embodiment of the second embodiment. On the other hand, S501
If it is not determined that the automatic ejection is necessary, the flow advances to S510 to check whether or not the information of the recording cancellation is input from the conveyance operation control means 206. If the recording is not canceled, the flow returns to S501. If the recording has been canceled, the flow advances to step S511 to set the automatic ejection flag 212, and then it is checked whether or not the feeding port of the printing sheet canceled in step S512 is a double-side refeeding port. If the canceled recording sheet is fed from the double-sided re-feeding port, the process proceeds to all in-machine sheet discharge control in S503 and below. If it is the other feeding port, the process proceeds to S513 and the destination of the recording sheet being fed is determined. The information is changed to the FD outlet 56, and the process proceeds to S507. At this time, as in the case of the first embodiment of the second embodiment, information on the number of sheets that must be re-recorded in the external host device 22 is not output. This is a case where the cancellation is normally performed by the judgment of the external host device 22, and
This is because the device 22 itself did not discharge the expected recorded sheet. Finally, in step S507, the automatic ejection flag 212 is reset, and the automatic ejection control ends.

FIG. 18 shows the procedure of the control operation by the automatic discharge necessity judging means 204 of the second embodiment of the second embodiment. First, the abnormality detection waiting in S601 is the same as that in S301 in FIG. 14, but if an abnormality is detected, the in-machine sheet counter 210 is checked in S602, and the number of in-machine sheets is not 0, and further the conveyance can be continued in S603. If the judgment is S
Proceeding to 604, an automatic ejection request is issued. Therefore, an abnormality occurs not only during recording but also when a recording sheet exists in the machine (for example, a state in which a recording sheet waiting for re-feeding is waiting in the double-sided conveyance mechanism and the laser beam printer 1 is waiting for a feeding instruction). In this case, an automatic discharge request is issued in all cases.

By performing control as described above, if an abnormality occurs in the apparatus, the apparatus can be stopped as much as possible without leaving any remaining sheet in the apparatus when sheet conveyance can be continued.

If the page order is different even when the recording is cancelled, the external host device 22 is notified of the number of sheets required to be re-recorded after all the in-machine sheets have been discharged, so that the correct page order can be obtained. Can be recorded.

(Third Embodiment of the Second Embodiment) In the first embodiment and the second embodiment of the second embodiment of the present invention, all the recording sheets automatically discharged are discharged from the FD discharge port 56. However, it is also possible to discharge from a discharge port different from the specified discharge port according to the discharge port specified at that time, and the discharge is controlled in this manner in the third embodiment of the second embodiment. The configuration of the device is the same as in the first and second embodiments of the second embodiment.

FIG. 19 shows the procedure of the control operation by the automatic discharge control means 207 of the third embodiment of the second embodiment. In the case of this example, the overall control is almost the same as the flow shown in FIG. 17, but S704 and S705 are different from S504 and S513. That is, the discharge destination of the recording sheet when all the internal sheets are automatically discharged in S604 and S613 is S504.
Instead of being fixed to the FD discharge port as in S513, the discharge destination is changed according to the destination specified at that time.

First, in step S701, destination information (set in the destination storage unit 209) of the recording sheet to be automatically ejected at that time is extracted, and the process proceeds to step S702.
If the information is destined for the double-sided conveyance mechanism in S706
Otherwise, the process proceeds to S703. Then, S7
03, it is checked whether the information is for the FD outlet 56 or not.
In the case of going to the D outlet, in S704 the FU outlet 57
If not, the designation of the destination is changed to the FD discharge port 56 in S705. If it is determined in step S702 that the double-sided conveyance mechanism is to be forwarded, in step S706, the destination information of the immediately preceding recording sheet is extracted and the processing proceeds to step S706.
Return to 2. Here, if it is the double-sided conveyance mechanism again, the process proceeds to S706 again. As described above, in the laser beam printer of the present embodiment, only two or less recording sheets can be simultaneously conveyed to the duplex conveying mechanism.
For this reason, when a recording instruction is issued from the external host device 22 in response to the designation of going to the two-sided conveyance mechanism for three consecutive sheets, the external device communication means 203 does not accept the recording instruction for the third recording sheet, and Device 22 by communication I / F
To inform the information specified by illegal. Therefore, by extracting the destination information of the recording sheet recorded at most three sheets before the destination from the destination storage means 209, it is possible to obtain the information of destination specification other than the two-sided conveyance mechanism. In this way, even if automatic ejection occurs while recording is continuously performed from the external host device 22, the recording sheet is ejected to an ejection port different from the ejection port designated by the external host device 22. Therefore, the page order of the completed document can be prevented from being changed, and unnecessary recording sheets can be prevented from intervening.

[0080]

As described above, the first aspect of the present invention is as follows.
According to the aspect, the sheet height detecting means for detecting the feeding height of the upper surface of the recording sheet, and the feeding height via the lifter based on a detection signal from the sheet surface height detecting means Means for correcting sheet feeding, and controlling the sheet feeding means by the sheet feeding means in accordance with the printing operation of the printer, and setting the sheet feeding means to the recording in a state where the printing operation of the printer is prohibited. The sheet feeding means is always pressed to the upper surface of the recording sheet except for the recording prohibited state, and the sheet is only in the recording prohibited state according to the state of the recording apparatus. It is possible to control the feeding means so that it is separated from the upper surface of the sheet, and it is possible to accurately check the height of the upper surface of the recording sheet and perform corrective operations at all times when the sheet is fed. , The recording disabled state such as when the recording sheet supply or when the jam treatment can be retracted so as not to interfere with the processing operation of the sheet feeding means.

According to the second embodiment of the present invention, when the automatic discharge necessity determining means determines that there is a need for automatic discharge, the automatic discharge is carried out based on the transport conditions stored in the storage means. The automatic discharge control means for controlling the recording sheet enables the rational discharge of the recording sheet being conveyed, not only prevents unnecessary use of the recording sheet, but also causes unnecessary operation of the external host device. Is not required, the load is reduced accordingly, and the recording sheet does not needlessly remain in the apparatus by appropriate automatic discharge control.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a circuit configuration according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a laser beam printer according to a first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a feeding mechanism in the laser beam printer according to the first embodiment of the present invention by a side surface (A) and a plane (B).

FIG. 4 is a flowchart illustrating a control operation procedure performed by a seat surface height correction unit according to the first embodiment of the present invention.

FIGS. 5A and 5B are explanatory views showing the difference in sheet surface height depending on the position of the pickup roller according to the first embodiment of the present invention in two forms (A) and (B).

FIG. 6 is a flowchart illustrating a control operation procedure of a pickup roller control unit according to the first example of the first embodiment of the present invention.

FIG. 7 is a flowchart illustrating a control operation procedure of a pickup roller control unit according to the second embodiment of the first embodiment of the present invention;

FIG. 8 is a block diagram showing a circuit configuration according to a third embodiment of the first aspect of the present invention;

FIG. 9 is a flowchart illustrating a control operation procedure of a pickup roller control unit according to a third embodiment of the first embodiment of the present invention.

FIG. 10 is a block diagram illustrating a circuit configuration according to a second embodiment of the present invention.

FIG. 11 is a sectional view showing a configuration of a laser beam printer according to a second embodiment of the present invention.

FIG. 12 is a block diagram showing an electrical configuration of the printer shown in FIGS. 10 and 11.

FIG. 13 is a flowchart illustrating a procedure of a control operation of a transport operation control unit according to the first example of the second embodiment of the present invention.

FIG. 14 is a flowchart illustrating a procedure of a control operation of an automatic discharge control unit according to the first example of the second embodiment of the present invention.

FIG. 15 is a flowchart illustrating a procedure of a control operation of an automatic discharge necessity determining unit according to the first example of the second embodiment of the present invention.

FIG. 16 is a flowchart illustrating a control operation procedure of a transport operation control unit according to a second example of the second embodiment of the present invention.

FIG. 17 is a flowchart showing a procedure of a control operation of an automatic discharge control means according to a second embodiment of the second mode of the present invention.

FIG. 18 is a flowchart illustrating a procedure of a control operation of an automatic ejection necessity determining unit according to a second embodiment of the second aspect of the present invention.

FIG. 19 is a flowchart showing a discharge port designation procedure at the time of automatic discharge according to the third embodiment of the second aspect of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Laser beam printer 2, 2U, 2D cassette 3 Image forming part 4 Feeding device 5, 5U, 5D Pickup roller (sheet feeding means) 6, 6U, 6D feed roller 8 Lifter 9 Sheet surface detection sensor 10 Sheet presence / absence detection sensor Reference Signs List 11 Cassette presence / absence detection sensor 12 Registration roller pair 13 Pre-registration sensor 14 Laser scanner unit 15 Fixing roller (fixing device) 16 Eject tray 20 Printer main controller 21 Interface unit 22 External host device 30 Self-diagnosis unit 31 State management unit 32 Recording and conveyance Control means 33 Feeding device control means 36 Sheet surface height correction means 37 Feeding control means 38 Pickup roller control means 39 Feeding / transporting control means 44 Drive motor 53 Double-sided flapper 55 Face-up (FA) flapper 56 Face-down (F ) Discharge port 57 FA discharge port 60 Discharge port sensor 61, 62 Double-sided roller 63 Double-sided detection sensor 65 Resupply roller 66 Resupply detection sensor 70 Branch point 80 Main control unit 201 Transport control unit 202 Self-diagnosis unit 203 External device communication unit 204 Automatic discharge necessity determination means 205 Transport information storage means 206 Transport operation control means 207 Automatic discharge control means 208 Feeding port storage means 209 Destination storage means 210 In-machine sheet counter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuzo Kiyono 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Izumi Narita 3- 30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A-3-2888731 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 1/00-3/68

Claims (2)

(57) [Claims] 1. A sheet capable of feeding the recording sheets one by one to an image forming section by a frictional force while being pressed against an upper surface of the recording sheets stacked on a stacking plate held vertically by a lifter. A conveying device of a printer having a feeding unit, wherein a sheet surface height detecting unit for detecting a feeding height of an upper surface of the recording sheet; and a lifter based on a detection signal from the sheet surface height detecting unit. A sheet surface correcting unit that corrects the feeding height by controlling the feeding operation of the sheet feeding unit in accordance with the printing operation of the printer, and the sheet in a state where the printing operation of the printer is prohibited. A feeding device for a printer, comprising: sending control means capable of controlling a feeding means to be pulled up from an upper surface of the recording sheet. 2. The apparatus according to claim 1, further comprising a standby portion or a conveyance path capable of holding at least one or more recording sheets other than the recording sheet, other than the external discharge conveyance path, and including the recording sheet. In a transport device of a printer capable of automatically discharging sheets to the outside of a machine, storage means for storing conditions related to transport, diagnostic means for diagnosing a functional state including at least a transport function of the printer, and information from the diagnostic means Automatic discharge necessity judging means for judging the necessity of the automatic discharge on the basis of the above, and when the automatic discharge necessity judging means judges the necessity, based on the conditions relating to the conveyance stored in the storage means And an automatic discharge control means for controlling the execution of the automatic discharge.