JP2010018379A - Image processing device, method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly determine the presence / absence of a sheet even when a sheet detecting means for detecting the presence / absence of a sheet on a conveyance path changes with time.
A system control unit 22 monitors an output level of a detection signal output from a conveyance path sensor 21 when conveying a sheet so as to send the sheet to a transfer unit of a process unit, and outputs it until the sheet is detected. When the level b is detected and the output level is detected to be increased by + c, it is determined that the sheet is detected by the conveyance path sensor 21, and it is determined that the sheet is on the conveyance path.
[Selection] Figure 4

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program including a facsimile machine, a printer, a copying machine, and a multifunction machine.

If an error is detected in each module including image formation, paper feed, conveyance, and fixing during printing, the printing operation is stopped according to the module in which the abnormality occurred, the operation is stopped after printing, or the printing is continued with the retraction operation. There was an image processing apparatus to be executed (see, for example, Patent Document 1).
In such an image processing apparatus, a conveyance path sensor that detects a sheet is provided on a conveyance path that conveys the sheet to a toner image transfer unit, and the output level of the detection signal of the conveyance path sensor is greater than or equal to a threshold value. The presence or absence of paper on the conveyance path is determined.
JP 2006-303569 A

However, in the conventional image processing apparatus, the threshold value for determining the presence / absence of paper is often a fixed value. When the conveyance path sensor deteriorates due to aging and the output level decreases, the presence / absence of paper on the conveyance path is determined. There was a problem that it could not be judged correctly.
The present invention has been made in view of the above points, and an object of the present invention is to make it possible to correctly determine the presence / absence of a sheet even if a sheet detecting means for detecting the presence / absence of a sheet on a conveyance path changes over time.

  In order to achieve the above object, the present invention provides an image forming means for creating a toner image, a transfer means for transferring the toner image produced by the image forming means to a sheet, and a sheet loaded on the sheet stacking means. Paper feeding means, a transport means for transporting paper fed by the paper feed means to the transfer means, a paper detection means for detecting paper transported by the transport means, and transport of paper by the transport means An image processing apparatus is provided that includes a determination unit that monitors the output level of the detection signal output from the sheet detection unit and determines that the sheet is on the conveyance path based on a change in the output level.

Further, based on the elapsed time from when the change in the output level of the detection signal output by the paper detection means is detected until the output level after the change continues and returns to the output level before the change again, It is preferable to provide a judging means for judging whether or not the length of the paper is appropriate.
Furthermore, an image processing method comprising steps corresponding to the functions of the respective means of the image processing apparatus and a program for causing a computer to execute the procedure of each step of the image processing method are also provided.

  The image processing apparatus according to the present invention can correctly determine the presence / absence of the paper detecting means for detecting the presence / absence of the paper on the conveyance path even if the paper is aged.

Hereinafter, a reference technique and the best mode for carrying out the present invention will be specifically described with reference to the drawings.
〔Example〕
FIG. 1 is a block diagram showing a functional configuration of a reference printer of the present invention and a laser printer according to an embodiment.
The laser printer 1 includes an optical scanning device 3 that optically scans a photosensitive member 2 as an image carrier in accordance with an image signal, a photosensitive member 2, a charging charger 4, a developing device 5, a transfer charger 6, and a cleaning device. 7 includes a process unit that performs an image forming process (image forming process) 7 and a transfer process.
Further, an upper paper feeding cassette 8 and a lower paper feeding cassette 9 for supplying paper, a fixing device 10 for thermally fixing a toner image developed by the developing device 5 and transferred onto the paper, and fixing processing by the fixing device 10 are performed. A lower discharge tray 12 and an upper discharge tray 13 for receiving sheets discharged through the discharge path 11 are provided.

The laser printer 1 also includes an optional large-volume paper feeding device 14 and a sheet on which a toner image is formed on one side fixed by the fixing device 10, and is sent back to the process unit to be fed with a toner image on both sides. Has a reversing device 15.
The upper sheet feeding cassette 8, the lower sheet feeding cassette 9, and the large amount sheet feeding device 14 are respectively provided with an upper sheet feeding roller 16, a lower sheet feeding roller 17, and a large amount sheet feeding roller 18 for sequentially feeding sheets. A registration roller pair 19 is provided in front of the photosensitive member 2 in the process unit to align the paper and the toner image on the photosensitive member 2 in the paper feeding direction (vertical registration adjustment).

The laser printer 1 executes various processes including image reading and printing under the control of a system control unit 22 of a microcomputer including a CPU, a ROM, and a RAM.
A program is stored in the ROM, and various functions of the laser printer 1 are realized by the CPU executing each procedure of the program using the RAM as a work area.
Under the control of the system control unit 22, data such as character codes sent from a host computer including a personal computer is converted into image data (image information) in page units by an internal controller (not shown), and one line Each time an image signal is output to the system control unit 22 in the engine driver, an image is printed (formed) on the paper.
That is, the photosensitive member 2 in the process unit is rotated in the direction of the arrow by a main motor (not shown), and the surface is first uniformly charged by the discharge from the charging charger 4, and then the optical scanning device 3 is used for writing. A laser beam modulated in accordance with the image signal is irradiated to form an electrostatic latent image (electrostatic image) corresponding to the written image, and toner is attached to the electrostatic latent image by the developing device 5 to form a toner image. An image forming process to be formed is performed (corresponding to a function of an image forming unit that forms a toner image).

On the other hand, the sheet is fed by driving any one of the upper sheet cassette 8, the lower sheet cassette 9, and the sheet feeding rollers 16 to 18 of the mass sheet feeding device 14 corresponding to the selected sheet. When the leading edge of the sheet is detected by the registration sensor 20, the leading edge of the sheet is pressed against the pair of registration rollers 19 based on the detection result to correct the skew of the sheet, and the feeding roller 16, 17, or 18 that is being driven temporarily Stop and wait for the paper (this corresponds to the function of the paper feeding means for feeding the paper stacked on the paper stacking means).
Then, the paper feeding roller 16, 17, or 18 that is temporarily stopped at a predetermined timing is driven, and the registration roller pair 19 is driven to feed the paper to the transfer unit of the process unit. The toner image is brought into contact with the photoconductor 2 and superimposed on the toner image, and a predetermined voltage is applied to the transfer charger 6 at a predetermined timing to attract the toner to the paper side, and the toner image on the photoconductor 2 is transferred onto the paper (above). This corresponds to the function of a transfer means for transferring the paper fed by the paper feed means to the transfer means and a toner image produced by the image forming means to the paper). The conveyance path sensor 21 is a sensor that detects the presence or absence of a sheet on a conveyance path that feeds the sheet to the transfer unit of the process unit, and corresponds to a function of a sheet detection unit that detects the sheet conveyed by the conveyance unit.

The paper separated from the photosensitive member 2 is sent from the process unit to the fixing device 10, and the fixing device 10 applies a process of heating and pressurizing the paper and the toner image to melt and fix the toner image on the paper. The processed sheet is discharged to the lower discharge tray 12 or the upper discharge tray 13 through the discharge path 11.
Further, after the transfer process is completed, the residual toner is removed by the cleaning device 7, and the residual charge is erased by irradiation of a static elimination lamp (not shown) to prepare for the next image forming process.

On the other hand, in the duplex mode in which images are printed on both sides of a sheet, the sheet on which a toner image is printed (transferred / fixed) on one side is sent to a reversing device (double-sided device) 15 and the front and back sides are reversed.
The paper whose front and back surfaces are reversed is re-fed from the reversing device 15 to transfer the toner image formed on the photosensitive member 2 again, and the photosensitive member is passed through the registration roller pair 19 in the same manner as in single-sided printing. 2, the toner image is transferred to the other surface, the toner image is thermally fixed by the fixing device 10, and the lower discharge tray 12 or the upper discharge is discharged via the discharge path 11. The paper is discharged to the tray 13.

Next, as a reference technique of the present invention, a threshold value determination process of the conveyance path sensor 21 in the system control unit 22 of the laser printer 1 will be described.
FIG. 2 is a flowchart showing the threshold value determination process of the conveyance path sensor in the system control unit of the laser printer shown in FIG.
The system control unit 22 feeds paper from any one of the upper paper feed cassette, the lower paper feed cassette, and the large-volume paper feeder at step (indicated by “S” in the figure) 1, and at step 2, the registration sensor When the leading edge of the sheet is detected to determine whether or not the sheet has reached the registration roller pair, if it is determined that the sheet has reached, the conveyance of the sheet is stopped in step 3, and the sheet is not on the conveyance path in step 4. Holding the output level of the detection signal of the conveyance path sensor, starting conveyance of the paper in step 5, holding the output level of the detection signal of the conveyance path sensor when the paper is on the conveyance path in step 6, Based on the output levels of the both detection signals held in step 7, a threshold value for determining the presence or absence of paper in the detection signal of the conveyance path sensor is determined, and in step 8, the determined threshold value is stored in a memory. End To.

As the memory, a non-volatile memory in the system control unit 22 (not shown in FIG. 1) may be used.
The output level of the detection signal of the conveyance path sensor 21 detected in a state where the paper is not on the conveyance path and the output level of the detection signal of the conveyance path sensor 21 detected in a state where the paper is on the conveyance path are It is good to store in the non-volatile memory in the system control part 22 similarly to a threshold value.
In this way, the threshold value for detecting the presence or absence of the sheet is corrected by the conveyance path sensor for each printing process, so that erroneous detection of the sheet can be prevented even if the conveyance path sensor is deteriorated due to aging.
As a result, the product life is extended with respect to deterioration of the conveyance path sensor due to aging, and it becomes unnecessary to select and deliver the sensor, so that the manufacturing cost of the image forming apparatus can be reduced.

Next, the threshold value correction process will be described.
FIG. 3 is a flowchart showing threshold correction processing in the system control unit of the laser printer shown in FIG.
In step (indicated by “S” in the figure) 11, the system control unit 22 determines whether or not the paper to be fed is a back paper. If the paper is a back paper, the system control unit 22 proceeds to step 12. . This determination may be made based on the paper setting information specified at the time of printing.
In step 12, the backing paper correction data held in advance is acquired. This backing paper correction data is data for correcting the output level of the detection signal when detecting the backing paper obtained in advance, and is, for example, held in the memory of the system control unit.
In step 13, based on the acquired backing paper correction data, the threshold value stored in the memory of the system control unit is corrected, and the threshold value in the memory is updated to the corrected value.

Next, in step 14, paper is fed from any one of the upper paper feeding cassette, the lower paper feeding cassette, and the mass paper feeding device, and in step 15, the leading edge of the paper is detected by the registration sensor, and the paper reaches the registration roller pair. If it has been reached, the conveyance of the paper is stopped in step 16, and the output level of the detection signal of the conveyance path sensor when the paper is not on the conveyance path is held in step 17. In step 18, the conveyance of the paper is started. In step 19, the output level of the detection signal of the conveyance path sensor when the paper is on the conveyance path is held, and in step 20, the output level of the both detection signals is held. Based on this, a threshold value for determining the presence or absence of the sheet in the detection signal of the conveyance path sensor is determined, the threshold value determined in step 21 is stored in the memory, and this process is terminated.
Similarly to the threshold value correction process, the density at the time of transfer to the paper may be determined based on the formed toner image, and the threshold value may be corrected based on the determined density. At this time, when determining the density at the time of transfer, it is better not to perform the density determination on the density portion which is a problem if it is determined that the presence or absence of the paper cannot be determined.

In this way, as the deterioration of the conveyance path sensor due to aging progresses, the upper and lower limit width that can be detected by the conveyance path sensor becomes narrower. Therefore, if the threshold is simply determined, the back paper that is printed in black is used. If a black portion is detected by detecting the presence or absence of paper by a conveyance path sensor, such as when performing double-sided printing, black printing on the front surface, and back marking, etc., there is a possibility of erroneous detection.
Therefore, the threshold value is corrected so that the density of the toner image transferred to the paper at the time of image formation is determined and the conveyance path sensor is not affected by the print density by correcting the threshold value in advance. Correction can be made to prevent false detection.
In addition, when the laser printer 1 has not been used for a certain period of time, the threshold value determination process may be executed to determine the threshold value again.
Further, it is preferable to hold the threshold value obtained for each paper type by the above processing and use the threshold value according to the paper type at the time of printing.

Next, processing for determining the presence or absence of a sheet on the conveyance path according to the embodiment of the present invention in the laser printer 1 shown in FIG.
When determining the presence or absence of a sheet on the conveyance path using the threshold value described above, the threshold value is periodically corrected so that the conveyance path sensor does not detect the sheet correctly due to a decrease in output level due to aging. Processing must be done.
Therefore, in the laser printer 1 of this embodiment, the presence / absence of a sheet on the conveyance path is determined without performing the above-described complicated correction processing and without using the threshold value.
For this purpose, the system control unit 22 monitors the output level of the detection signal output from the conveyance path sensor 21 when the sheet is conveyed in order to send the sheet to the transfer unit of the process unit, and the sheet is based on the change in the output level. It fulfills the function of a determination means for determining that is on the transport path.

FIG. 4 is a waveform diagram for explaining the determination process of the presence / absence of the sheet on the conveyance path according to the embodiment of the present invention in the system control unit of the laser printer shown in FIG.
In the figure, the vertical axis indicates the voltage value of the output level of the detection signal of the transport path sensor 21, and the horizontal axis indicates the passage of time, and the waveform 30 in the figure transports the sheet to the transfer unit of the process unit during transport. An example of the change in the output level of the detection signal of the road sensor 21 is shown.
For example, when determining the presence or absence of a sheet on the conveyance path using a threshold value as in the prior art, if a = 3V in the figure is set to the above threshold value, the output level of the detection signal of the conveyance path sensor 21 decreases, and the sheet is If the output level at the time of detection is less than the threshold value a = 3V, the presence / absence of paper cannot be determined correctly.

However, in the laser printer 1 according to the embodiment of the present invention, the system control unit 22 monitors the output level b of the detection signal output from the transport path sensor 21 before transporting the paper to the transfer unit of the process unit. When the sheet is transported in order to send the image to the transfer unit of the process unit, the output level of the detection signal output from the transport path sensor 21 is monitored, and when it is detected that the output level has increased by c, the transport path sensor 21 is detected. It is determined that the sheet is detected by the above, and it is determined that the sheet is on the conveyance path.
In this way, it is not necessary to determine the presence / absence of the sheet by comparing the output level of the detection signal and the threshold value, and even if the output level is lowered due to deterioration of the conveyance path sensor 21 over time, the threshold value correction processing is performed. The presence / absence of paper can be correctly determined without performing such complicated processing.

Next, the system control unit 22 may determine whether or not the paper length is appropriate.
In this case, the system control unit 22 detects a change in the output level of the detection signal output from the conveyance path sensor 21 until the output level after the change continues and returns to the output level before the change again. It also functions as a determination means for determining whether or not the paper length is appropriate based on the elapsed time.
FIG. 5 is a waveform diagram for explaining a determination process for determining whether or not the length of the conveyed sheet is appropriate in the system control unit of the laser printer shown in FIG. 1 according to the embodiment of the present invention. .
As in FIG. 4, the vertical axis indicates the voltage value of the output level of the detection signal of the conveyance path sensor 21, and the horizontal axis indicates the passage of time, and the waveform 31 in FIG. The other example of the change of the output level of the detection signal of the conveyance path sensor 21 at the time of conveyance to the transfer part of a unit is shown.

For example, when the presence / absence of a sheet on the conveyance path is determined using a threshold as in the conventional case, the output level of the detection signal output from the conveyance path sensor 21 is lower than the time t2 when the threshold a = 3V is exceeded. Although it is possible to determine the length of the sheet based on the time up to time t3, the change in the output level of the detection signal output from the transport path sensor 21 is actually a detection signal output from the transport path sensor 21. When the output level b is increased by an increase amount d that does not exceed the threshold value a = 3V, the detection of the sheet starts, and thereafter, the change increases by an increase amount e that exceeds the threshold value a = 3V. May show.
In such a case, an elapsed time t3-t1 from time t1 when detecting the level amount in which + d is added to the output level b of the detection signal of the conveyance path sensor 21 to time t3 when the output level falls below the threshold value a. The length of the paper is obtained based on the transport amount (value stored in advance) in the unit time of the paper, and it is determined whether or not the paper length is appropriate based on the length. If it is confirmed that the length is normal, the process is continued.

  The image processing apparatus, the image processing method, and the program according to the present invention can be applied to all image processing apparatuses including a facsimile machine, a printer, a copying machine, and a complex machine thereof.

It is a block diagram which shows the function structure of the reference technology of this invention and the laser printer of an Example. FIG. 2 is a flowchart showing a threshold value determination process of a conveyance path sensor in a system control unit of the laser printer shown in FIG. 1 as a reference technique of the present invention. FIG. 2 is a flowchart showing a threshold correction process of a conveyance path sensor in a system control unit of the laser printer shown in FIG. 1 as a reference technique of the present invention. FIG. 3 is a waveform diagram for explaining a process for determining whether or not there is a sheet on a conveyance path according to an embodiment of the present invention in the system control unit of the laser printer shown in FIG. 1. FIG. 2 is a waveform diagram for explaining a determination process for determining whether or not the length of a conveyed sheet according to an embodiment of the present invention is appropriate in the system control unit of the laser printer shown in FIG. 1.

Explanation of symbols

1: Laser printer 2: Photoconductor 3: Optical scanning device 4: Charging charger 5: Developing device 6: Transfer charger 7: Cleaning device 8: Upper paper feeding cassette 9: Lower paper feeding cassette 10: Fixing device 11: Paper ejection path 12: Lower paper discharge tray 13: Upper paper discharge tray 14: Mass paper feeder 15: Reversing device 16-18: Paper feed roller 19: Registration roller pair 20: Registration sensor 21: Conveyance path sensor 22: System controller

Claims (5)

  Image forming means for creating a toner image, transfer means for transferring the toner image created by the image forming means to paper, paper feed means for feeding the paper loaded on the paper stacking means, and the paper feed means A conveying means for conveying the fed paper to the transfer means; a paper detecting means for detecting the paper conveyed by the conveying means; and a detection signal output by the paper detecting means when the paper is conveyed by the conveying means An image processing apparatus comprising: a determination unit that monitors the output level of the image and determines that the sheet is on the conveyance path based on a change in the output level.   Based on the elapsed time from when the change in the output level of the detection signal output by the paper detection means is detected until the output level after the change continues and returns to the output level before the change again. The image processing apparatus according to claim 1, further comprising a determination unit that determines whether or not the length is appropriate.   An image forming process for creating a toner image, a transfer process for transferring the toner image generated in the image forming process to a sheet, a sheet feeding process for feeding a sheet, and a sheet fed by the sheet feeding process Monitoring the output level of the detection signal output from the paper detection step when the paper is conveyed by the conveyance step, the paper detection step of detecting the paper conveyed by the conveyance step, and the conveyance step of conveying to the transfer step; An image processing method comprising: a determination step of determining that the sheet is on a conveyance path based on a change in the output level.   Based on the elapsed time from when the change in the output level of the detection signal output in the paper detection step is detected until the output level after the change continues and returns to the output level before the change again. 4. The image processing method according to claim 3, further comprising a determination step of determining whether or not the length is appropriate.   A program for causing a computer to execute a procedure of each step of the image processing method according to claim 3 or 4.

Images