JPS6392549A - Laser printer - Google Patents

Abstract

PURPOSE:To improve the extent of operability sharply, by installing a counter for the number of sheets of paper existing in a paper conveying passage and, when it is one sheet along, making error state releasing operation after solution of a paper jam at a paper discharge port eliminable. CONSTITUTION:Plural jams inclusive of at least a first jam 4 and a last jam 5 are set up in a paper conveying passage 3 leading from a paper feeding mechanism 1, and there is provided with a paper counter 8 which counts up paper in response to its passage at the first jam 4 and counts down it in response to the passage at the last jam 5. And, when the counted value of this paper counter 8 has showed 1, a paper jam error state is made to as to be released to 'no error release operation' with a simplified paper jam error state releasing device 9 in response to the paper jam solution operation that a paper jam detecting device 6 performed after detecting the paper jam at a final jam position. Therefore, a burden on an operator is lightened and operability is sharply improvable.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to laser printers, and in particular, the present invention relates to laser printers, and particularly to the prevention of paper jams when a paper jam occurs in the paper conveyed along the paper conveyance path from the paper feed mechanism to the paper ejection port. The present invention relates to a laser printer with an improved operation for canceling an error state.

[Prior Art] Generally, in a laser printer, a charging unit that charges the photosensitive drum, for example along the circumference of the photosensitive drum rotating at a constant speed, is installed inside the case, and a charging unit that responds to character data input from the outside is installed in the case. an exposure section that scans a laser beam in the axial direction of the photosensitive drum in response to an image signal generated by the photosensitive drum; a developing section that develops the image formed on the photosensitive drum; A transfer section that transfers the image onto a sheet of paper supplied from the outside, a static elimination section that erases the image on the transfer section, and the like are provided. Furthermore, a cassette containing a large number of sheets is disposed at the bottom of the case, and a heat fixing section is provided on one side of the case.

Then, when you press the start key on the operation panel provided on the outside of the case, the photosensitive drum starts rotating, an image is created in the exposure section on the photosensitive surface of the photosensitive drum whose static electricity has been removed, and this image is developed in the development section. Then, head to the transcription department. In the transfer section, the image is transferred onto sheets of paper pulled out one by one from the cassette by a CF roller. The paper onto which the image has been transferred is transported to a heat fixing section by a transport roller, and the transferred image is thermally fixed by the heat fixing roller. The paper that has passed through the heat fixing section is discharged out of the case from the paper discharge port at the discharge row.

In a laser printer configured in this way, the paper fed from the cassette may wrap around each roller or may not be conveyed smoothly during the process before it is ejected from the case through the paper ejection port. Paper jam phenomenon often occurs. Therefore, in general laser printers, jams are installed at multiple positions in the paper conveyance path from the cassette to the paper ejection port, so that when a paper jam occurs, it can be detected and the position of occurrence can be determined. I am trying to detect it as well. When a paper jam is displayed, the operator opens the cover on the side of the case and removes the paper in the paper transport path.Then, when the operator closes the cover, the paper jam error condition is cleared and the operator presses the start key on the operation panel. The state becomes operational.

[Problems to be Solved by the Invention] However, even in the laser printer in which the paper jam error state is canceled as described above, there are the following problems. That is, there is a possibility that paper jams may occur at any position in the paper conveyance path within the case. Therefore, paper jams may also occur at the paper ejection port.

In such a case, it is easy to remove the paper jammed in the paper outlet without opening the cover on the side of the case. However, even if the paper jammed in the paper outlet is removed in this manner, the paper jam error state will not be cleared unless the cover on the side of the case is opened and then closed again.

Therefore, it is necessary for the operator to carry out extra operations such as opening and closing the cover. As a result, there is a problem in that the operation becomes complicated and the operability of the laser printer as a whole deteriorates.

The present invention is provided with a counter that counts the number of sheets of paper present in the paper conveyance path, and when the number of sheets of paper is one, it is possible to eliminate the operation to clear the error state after clearing the paper jam at the paper ejection port, greatly improving operability. The objective is to provide an improved laser printer.

[Means for Solving the Problems] As shown in FIG. A plurality of jams including a leading jam 4 near the paper mechanism 1 and a final jam 5 near the paper ejection port 2 are arranged, and paper passage is not detected for each jam within a predetermined time from the start signal input time. At this time, the paper jam detection means 6 detects a paper jam at each jam setting position and sets the paper jam error state, and releases the paper jam error state in response to an error release operation performed after the paper jam clearing operation at the designated jam position. The paper jam error state is canceled by the means 7, and a paper counter 8 is provided which counts up in response to the passage of paper at the first jam and counts down in response to the passage of paper at the final jam. When shown,
IaI! performed after the paper jam detection means 6 detects the paper jam at the final jam position. In response to the i-resolving operation, the simple paper jam error condition release means 9 releases the paper jam error state without any error release operation.

[Operation] In the laser printer configured in this manner, the number of sheets of paper present in the paper conveyance path is constantly counted by the paper counter. When a paper jam occurs due to a jam in one of the paper transport paths, a paper jam detection means determines a paper jam error state. Then, when a paper jam clearing operation is performed and a predetermined error state canceling operation is performed, this paper jam error state is cleared.

In addition, if the paper jam error state is detected at the final jam near the paper ejection port, the paper jam error state will be automatically cleared when the paper jam clearing operation is performed only when the paper counter is 1. It will be canceled. Therefore, in this case, there is no need to perform a separate error cancellation operation.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a side view showing a schematic configuration of the laser printer of the present invention. In the figure, reference numeral 11 denotes a case that covers the whole, and a cover (not shown) is attached to the side surface of the case 11 parallel to the plane of the drawing, and when this cover is opened, the internal structure shown in FIG. 2 is exposed. That is, a photosensitive drum 12 having a photosensitive surface formed on its outer peripheral surface is located at a central position inside the case 11.
The photosensitive drum 12 is rotated clockwise at a constant speed by a main drive motor 13. Along the outer periphery of the photosensitive drum 12, a charging section 141 consisting of a charging charger emits laser light in response to an image signal! ! The exposure section 15 outputs 46. A developing section 16 that develops the image formed on the photosensitive drum 12 by the n-tip section 15. A transfer unit 18 consisting of a transfer charger that transfers the developed brass onto the paper 17 supplied from the cassette 20. A snow removal section 19 consisting of a static elimination lamp for erasing the transferred image is provided.

Further, a cassette 20 for continuously supplying paper 17 to the transfer section 18 is inserted into the bottom of the case 11 from outside the case 11 . The paper 17 stored in the cassette 2o is pulled out one by one from the cassette 20 by the CF roller 21, and then transferred to the PF (paper feed) rollers 22a, 22b, 22
c to the transfer section 18. The image on the photosensitive drum 12 is transferred at this transfer section 18 . The paper 17 on which the image has been transferred is transferred to a heat fixing roller 23. Carrying out roller 24a.

The paper is discharged out of the case 11 from the paper discharge port 25 via the paper 24b.

Note that in the paper transport path of the paper 17 from when the paper 17 is pulled out from the cassette 20 until it is ejected from the paper ejection port 25, the paper is held between rollers 22b, 24a, and 24b, and the paper 17 is Leading jam 26a detects occurrence of jam.

An intermediate jamb 261) and a jll end jamb 26c are attached. Furthermore, a paper end (PF) sensor 27 is disposed within the insertion opening of the cassette 20 in the case 11 to detect when the number of remaining sheets of paper 17 in the cassette 20 becomes less than or equal to a specified number.

The exposure section 15 is configured as shown in FIG. 3, for example. That is, an octagonal polygon mirror (rotating polygon mirror) 42 is arranged near the apex inside the case 41, and a reflecting mirror 43 is arranged along the bottom side. The case 41 is positioned so that the reflecting mirror 43 is parallel to the axis of a photosensitive drum (not shown). Further, an fθ lens 44 is disposed between the polygon mirror 42 and the reflection 143. A laser beam 46 outputted from a laser diode 45 attached to the inner surface of the case 41 is reflected by one reflecting surface 7 of the polygon mirror 42, passes through an fθ lens 44, is reflected by a reflecting mirror 43, and is exposed to light. The drum is irradiated. However, the polycon mirror 42 becomes 1/
After eight rotations, the laser beam 46 is scanned from one end of the reflecting mirror 43 to the other end. That is, the photosensitive drum is scanned by one width in the axial direction.

FIG. 4 is a block diagram showing a schematic configuration of a laser printer. CPU (Central Processing Unit) that performs various calculation processes
31 is a ROM 33.33 which stores fixed data such as a control program via a pass line 32. RAM that stores variable data such as input character data and various flags
34, an interface 35 through which character data to be printed is input from an external host computer. Controls an input/output port 37 that inputs and outputs various commands and data to and from various constituent members. The input/output boat 37 includes a main drive motor 13. which rotates the photosensitive drum 12. Charging section 14 consisting of a charging charger; Transfer section 18 consisting of a transfer charger. Static eliminator 19 consisting of a static eliminator lamp. Drive motors for various O-ra.

A laser diode drive control circuit 38 that drives and controls the laser diode 45 of the exposure section 15. A paper end (PE) sensor 27, three jams 268 to 260, etc. are connected.

In the RAM 34, as shown in FIG. 5, a paper counter R1 for counting the number N of sheets of paper 17 existing in the paper transport path and a flag area IR2 for storing various flags are formed. In this flag area R2, there is a JAMa holding flag indicating that the paper 17 has not yet reached the leading jam 26a provided near the cassette 20 within a predetermined time from the start signal input time. The JAMb error flag indicates that the paper 17 has not reached the jam 26b, and the JAMb error flag also indicates that the paper 17 has not reached the final jam 26c within a predetermined time.
An AMC error flag, a final error flag indicating that the paper 17 is caught only in the final jam 26C in the paper conveyance path, a polygon error flag indicating that an asynchronous error has occurred in the polygon mirror 42, and a stop of the main drive motor 13. a heater error flag that indicates that the heat fixing roller 23 is out of a predetermined temperature range, a cover open flag that indicates that the cover of the case 11 mentioned above is open, and a paper end (PE) sensor 27. A paper end flag, etc., indicating that the paper 17 in the cassette 20 has been detected to be less than a predetermined number of sheets, is stored.

The CPU 31 is programmed to execute the main routine shown in FIG. 6 when the power of the apparatus is turned on. That is, when the power is turned on, the RAM
34 paper counters R1 and various initial processes including clearing of each flag in the flag area R2. Then P.O.
Flag area IUR corresponding to each jam 268~26G
2 JAMa holding flag, JAMb error flag, JA
Confirm that both MC error flags are cleared to 0. In this case, if there is a flag set to 1 in PO, the cover will be opened and paper jam removal will be performed.
When the cover is closed again, it is confirmed that the g-clog error state has been canceled and the process proceeds to the next step.

When the above is confirmed, the heat fixing roller 23 is
The heater is energized and the temperature is raised to a predetermined temperature. Next, check the state of the final jam 26c at R2 and
Execute AMC check processing. In FIG. 7, when the flow starts, the flag area 1if of the RAM 34
After confirming that the final error flag of flR2 remains cleared to 0, the process returns to the main routine of FIG. Note that if the final error flag is set to 1, it is checked whether the paper 17 is present in the final jam 26c. If it exists, the process returns to the main routine; if it does not exist, the final error flag is reset to 0 and the process returns to the main routine.

At R3 of the main routine in FIG. 6, it is checked that the cover is not open. If it is open, set the cover open flag to 1. Next, in R4, flag area R2
Confirm that the motor stop flag remains set to O. Note that if it is set to 1, the main drive motor 13 is stopped. At roughly R5, the PE sensor 27 confirms that there are more than a specified number of sheets w117 in the cassette 20. Next, in R6, turn on the test switch.
Check off. At R7, it is determined whether the paper 17 is to be supplied manually one by one or automatically using the cassette 20.

When the initial confirmation processing of P1 to P7 is completed, the signal output processing in the input/output boat 37 shown in FIG. 8 is executed in R8. When the flowchart of FIG. 8 is started, it is confirmed that the polygon error flag, heater error flag, cover open flag, etc. in the flag area R2 remain set to 0. If set to 1, an error signal is output and the REQ signal is set to H level. That is, it is in an error state and the next operation signal from the operation panel is not accepted.

Next, at P9, J A M a = J A M C (7
) Check that the error flag (wait flag) is cleared to O. If it is set to 1, it is determined that v1 jam has occurred and a paper jam error status signal is output, and an error signal is output. Furthermore, the paper end flag is set to O in Plo.
Make sure it remains unlocked.

Then, if a paper jam error state signal and an error signal are being output, these are stopped. Then, the REQ signal goes high.
If it is, it returns to the normal L level. That is,
Accepts the next operation signal from the operation panel.

Note that if the paper end flag is set to 1 in Plo, the process advances to PI3. If manual paper feeding is selected in PI3, the process returns to Pll. If automatic paper feeding is selected in PI3, an error signal is output and the REQ signal is set to H level. Thereafter, the process returns to the main routine shown in FIG.

When a start signal is input from the operation panel at P13 of the main routine of FIG. 6, the timing control process of FIG. 9 is executed at PI3. That is, FIG. 9 shows the elapsed time from the start signal input time for the first time (elapsed time TI>,
2nd time (elapsed time T2), 3rd time (elapsed time T3),
Divide into 4 times (Tl < T2) at the 4th time (elapsed time T4)
<T3<T4), the same stage process shown in FIG. 10 is executed every time each elapsed time elapses. It should be noted that each stage process from the first to fourth times indicates printing a character image on one sheet of paper, and four times automatically prints on four sheets of paper.

When the stage processing shown in FIG. 10 is started, the CF roller 2
1 and the laser diode 45 are activated. Next, it is checked whether the paper 17 is present at the position of the leading jam 26a.

If it exists, the number of sheets N of paper counter R1 is displayed at P16.
1 is added to , and the charging section 14 is activated. When the PI 3 confirms that the polygon mirror 42 is rotating normally, the printing range is set and the PF (paper feed) O-ra 22a is set.

22b, 22c and the transfer section 18 are activated. moreover,
At P18, it is checked whether the paper 17 is present in the intermediate jam 26b. Then, paper 1 reaches the intermediate jam 26b position.
7 has reached, the PF rollers 22a, 22b, 22
c and the transfer section 18 is stopped.

Thereafter, when it is confirmed in Plo that the paper 17 has reached the final jam 26c, it is confirmed in P2O that the paper 17 has not stopped at the intermediate jam 26b. MoteP
At 21, the state of the final jam 26G is checked again. Then, it is confirmed that the paper 17 has passed through the final jam 26c and has been discharged from the paper discharge port 25 to the outside of the case 11. Thereafter, in P22, the number N of sheets in the sheet counter R1 is subtracted by 1. This completes the printing process for one sheet of paper 17. Then, the process returns to the routine shown in FIG.

Note that if the paper 17 has not yet reached the leading jam 26a in PI3, the JAMa holding flag is set to 1 and the process returns to the routine of FIG. If the rotation of the polygon mirror 42 is not synchronized at PI3, the polygon error flag is set to 1, and the motor stop flag is set to 1, and the process proceeds to P22. Furthermore, if the paper 17 has not reached the intermediate jam 26b in P18, a paper jam has occurred, so the JAMb error flag is set to 1, the motor stop flag is set to 1, and the process proceeds to P22. Also,
If the paper 17 has not reached the final jam 26c in Plo, it is determined that a paper jam has occurred, and the JAMc error flag is set to 1 and the motor stop flag is set to 1. Furthermore, if the paper 17 is present in the intermediate jam 26b at the time of P2O, a paper jam has occurred, so the JAMb
Set the error flag to 1 and set the motor stop flag to 1.

Further, if the paper 17 is present in the final jam 26c at the time of P21, the JAMc error flag is set to 1 since it is naturally a paper jam. Then, in P23, the number of sheets on the sheet counter R1 is checked. At this point, the number of sheets of paper N is 2.
In the above case, there is other paper in the paper conveyance path other than the paper caught in the final jam 26G, so the process directly proceeds to P22.

If the number of paper sheets N is 1 at the time of P23, there is only paper in the paper conveyance path that was caught in this final jam 26c, so instead of clearing the JAMc flag to 0, set the final error flag to 1. Set.

After that, proceed to P22.

In the routine shown in Figure 9, even if one stage processing is not completely completed, the next stage processing will start when the time for the next time is up, so if multiple sheets are specified for printing, The sheets 17 are carried out one after another from the cassette 20. Therefore, a plurality of sheets can be stored in the paper transport path.

There will be paper. When it is confirmed in P24 that all stage processing has been completed, the motor stop flag is set to 1 and the process returns to the main routine of FIG.

In a laser printer configured in this manner, when a paper jam occurs in the first jam 26a, intermediate jam 26b, or final jam 26c, the JAMa holding flag and JAMb error flag corresponding to each jam are set.

The JAMC error flag is set to 1. By displaying these flag states on the operation panel, the location where the paper jam has occurred can be confirmed. Then, when the paper jam is cleared and the cover is closed at PO in FIG. 6, the paper jam error state is canceled and the system returns to its original state.

In addition, when a paper jam occurs in the final jam 26c, it is displayed on the display panel in the same manner as described above, but in this case, if there is another paper in the paper conveyance path in addition to the jammed paper, the above-mentioned The paper jam error condition is cleared by the processing at the PO.

In addition, when a paper jam occurs in the final jam 26C, if only the jammed paper is present in the paper conveyance path,
The AMC error flag is cleared and the final error flag is set to 1 instead. In this case, the final error flag is reset to 0 in the subroutine of FIG. 7 at P2 of the main routine for the sixth cause. In other words, the paper outlet 25
When the jammed paper 17 is removed from the paper jam, the final error flag is cleared to 0 and the apparatus returns from the paper jam error state unless the cover is opened/closed. That is, the simple paper jam error state canceling means is executed.

In this way, when a paper jam occurs in the final jam 26c provided near the paper ejection port 25, if there is no other paper in the paper conveyance path, the jammed paper can only be removed from the paper ejection port 25. , it is possible to clear the paper jam error state without opening or closing the cover.

Therefore, the burden on the operator can be reduced, and the operability of the entire laser printer can be significantly improved.

[Detailed Description of the Invention According to the present invention, a counter is provided to count the number of sheets of paper present in the paper conveyance path, and when the number of sheets in use is one, an error is detected after clearing the paper jam at the paper ejection port. It is possible to remove state release operations. Therefore, the burden on the operator can be reduced and the operability of the entire laser printer can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing the present invention, Figs. 2 to 10 show a laser printer according to an embodiment of the present invention, Fig. 2 is a side view when the cover is opened, and Fig. 3 is a side view when the cover is opened. 4 is a block diagram showing the entire structure, FIG. 5 is a diagram showing the main memory of the storage section, and FIGS. 6 to 10 are flowcharts showing the operation. 11... Case, 12... Photosensitive drum, 14...
Charging section, 15... Exposure section, 16... Development section, 17.
... Paper, 18 ... Transfer section, 19 ... Static elimination section, 20
...Cassette, 25...Paper outlet, 26a...
First jam, 26b...Intermediate jam, 26c...Final jam, 31...CPLJ, 33...ROM, 3
4...RAM. 37'... Input/output boat, 38... Laser diode drive control circuit, 41... Case, 42... Polygon mirror, 43... Reflector, 44... fθ lens,
45... Laser diode, 46... Laser beam.

Claims (1)

[Claims] At least a charging section, an exposure section, a developing section, and a transfer section are sequentially arranged along the circumference of a photosensitive drum disposed in a case, and the exposure section is placed on the sight surface of the photosensitive drum charged by the charging section. The image formed in the image forming section and developed in the developing section is transferred to the paper fed from the paper feeding mechanism in the transfer section, and the paper onto which the image has been transferred in the transfer section is transferred to the fixing section. In the laser printer, the laser printer is configured to eject the paper from the paper ejection port to the outside of the case through the paper feed mechanism, and a paper transport path that guides the paper supplied from the paper feed mechanism to the paper ejection port; A plurality of jams including a leading jam located near the paper feeding mechanism and a final jam located near the paper ejection port are detected, and paper passage is detected for each jam within a predetermined time from the start signal input time. a paper jam detection means that detects a paper jam at each jam setting position and sets a paper jam error state when there is no paper jam; a paper jam error condition release means for canceling the error condition; a paper counter that counts up in response to the passage of paper in the first jam and counts down in response to the passage of paper in the final jam; 1, the paper jam error state is cleared without the error clearing operation in response to a paper jam clearing operation performed after the paper jam detecting means detects the paper jam at the final jam position. A laser printer comprising a paper jam error state release means.