JP7202521B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having a function of detecting physical property values of recording paper with a media sensor on a transport path.

The printer transports recording paper under optimal paper transport control conditions for each paper type, thereby preventing jams from occurring. The paper transport control conditions include the paper transport speed, the interval between the preceding paper and the succeeding paper, jam detection time margin, transfer current, fixing temperature, and the like.

Conventionally, the paper type of the recording paper loaded in each paper tray is manually set by the user. It is determined based on the type of paper used. However, since there are various types of paper, the user may not always be able to set the correct paper type, resulting in the problem of jamming.

In recent years, a media sensor that measures physical property values such as the smoothness and paper thickness of the recording paper is installed on the transport path, and the paper type is automatically determined based on the physical property values obtained by measuring the recording paper being transported by the media sensor. Printers are appearing that have media detection functions that can be set to However, in order to detect the media, it is necessary to temporarily stop the recording paper being conveyed at a location where the media sensor is located, which reduces the productivity of the printer.

In order to avoid the decrease in productivity due to media detection, for example, there is a technique of detecting the first sheet of recording paper during various start-up operations at the start of printing. However, in order to improve the detection accuracy, the transport is stopped, one point is measured, and after the measurement of that point is completed, the transport is stopped for a while, and then the next point is measured. Therefore, it is not possible to complete the media detection only during the start-up operation time. Also, when detecting media, it is necessary to prevent jams from occurring between the paper feed tray and the media detection position at least while the correct paper type is unknown. When paper feed control is performed, paper feed takes longer than usual, and media detection cannot be completed only during the start-up drive time.

Therefore, in this type of printer, as a method of setting the paper type for the paper feed tray, there is a user setting mode in which the user sets the paper type, and an automatic setting mode in which the paper type is automatically set by detecting the media with a media sensor on the transport path. If the type of paper is known, use the user setting mode to increase productivity, and if the type of paper is unknown, use the automatic setting mode to avoid jams. I was trying to get it.

For the above setting modes, select the user setting mode on purpose to prioritize productivity even if the paper type is unknown, and then switch to the automatic setting mode after the jam occurs. In some cases, it is done. In this usage, it takes time and effort to switch to the automatic setting mode after the occurrence of a jam, or if the user forgets to switch to the automatic setting mode, the jam reoccurs, resulting in a further loss of time. Moreover, if media detection is performed when printing is resumed after the jam is cleared, the productivity is lowered due to the media detection operation.

As a technique for automatically setting the paper type of jammed paper based on media detection, for example, the following Patent Document 1 discloses that a media sensor detects the medium for each print, and when a jam occurs, the new paper type is determined based on the media detection data of the jammed paper. A printer is disclosed that is automatically generated to prevent future jams.

In addition, it has an automatic setting mode and a user setting mode. In the user setting mode, the media is detected when there is a margin (for example, when registration is stopped for the first print). There is a printer that omits this (see Patent Document 2 below).

Patent Document 3 below discloses an automatic setting mode and a user setting mode, in which the media is detected even in the user setting mode, and when switching to the automatic setting mode, the fixing temperature is detected before the recording paper reaches the media detection sensor. A printer has been disclosed in which temperature control waiting time is saved by switching the temperature in advance.

JP 2008-175989 A JP 2009-265627 A JP 2017-138406 A

In Patent Documents 1 and 2, medium detection for jammed paper is performed during printing before jamming occurs. However, it is not always possible to secure enough time for media detection during printing. Ultimately, printer productivity is reduced due to media sensing. Although the technology disclosed in Japanese Patent Application Laid-Open No. 2002-300001 detects the medium even in the user setting mode, it takes time to detect the medium, so productivity is sacrificed even in the user setting mode.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of detecting jammed paper without lowering productivity.

The gist of the present invention for achieving this object lies in the following inventions.

[1] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
When the jam detection unit detects a jam of the recording paper, the conveying unit is caused to perform a purge operation to convey the recording paper remaining in the conveying path to a predetermined paper discharge destination, and the recording paper remaining in the conveying path is controlled. a control unit that causes the media sensor to measure physical property values of the paper when the purge operation is executed;
An image forming apparatus comprising:

In the above invention, when a purge operation is performed when a jam occurs, media detection is performed on the recording paper conveyed along with the purge operation.

[2] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The image forming apparatus according to claim 1, wherein, if the jammed recording paper has been measured by the media sensor, the control unit does not perform the measurement when the purge operation is performed.

In the above invention, if the jammed paper has already been detected as a medium, the medium is not detected when the purge operation is executed.

[3] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit causes the media sensor to measure only recording paper fed from the same paper feed tray as the jammed recording paper among the recording papers transported during the execution of the purge operation. image forming device.

In the above invention, in the purge operation, media detection is performed only for recording paper from the same feeding source as the jammed paper.

[4] When the jammed recording sheet and the recording sheet from the same paper feed tray as the paper feed source do not remain in the conveying path upstream of the media sensor, the control unit, when executing the purge operation, The image forming apparatus according to [3], wherein the recording paper is fed from the same paper feed tray as the paper feeding source of the jammed recording paper, and the media sensor measures the recording paper.

In the above invention, if there is no recording paper from the same paper feed source as the jammed paper in the remaining paper after the jam occurs, new paper is fed from the same paper feed tray as the jammed paper when the purge operation is executed, and media is detected. do.

[5] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit is characterized in that the control unit controls the transport order of the recording paper to be transported when the purge operation is performed so that the recording paper to be measured by the media sensor is preferentially transported to the discharge destination . Image forming device.

In the above invention, by detecting the medium at an early stage, it is possible to reflect the result of the medium detection and execute the subsequent purge operation.

[6] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit determines whether or not to cause the media sensor to measure physical property values of the recording paper conveyed during execution of the purge operation, according to the type of jam detected by the jam detection unit. image forming apparatus.

In the above invention, it is determined whether or not to detect the media during the purge operation depending on whether or not the jam is caused by misidentification of the paper type.

[7] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
A user setting mode in which the user sets recording paper information to be linked to a paper feed tray, and a media sensor that measures the recording paper fed from the paper feed tray during image formation and transported, and based on the measurement results, the paper is fed. It has an automatic setting mode that automatically sets the recording paper information linked to the paper tray,
The image forming apparatus, wherein the control unit sets conditions for conveying recording paper fed from the paper feed tray based on recording paper information linked to the paper feed tray.

In the above invention, when a jam occurs in the user setting mode, media detection is performed by piggybacking on the purge operation.

[8] a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has

Based on the recording paper information linked to the paper feeding tray, the control unit sets the conveying conditions of the recording paper fed from the paper feeding tray and conveyed when the purge operation is executed. Recording paper information obtained by measuring, with the media sensor, the jammed recording paper and the recording paper having the same paper feed tray as the paper feed source is used as the paper feed source of the jammed recording paper. An image forming apparatus characterized by being tied to a paper feed tray.

In the above invention, recording paper from the same paper feed source as the jammed paper is detected when the purge operation is executed, and recording paper information for the paper feed tray of the paper feed source is automatically set.

According to the image forming apparatus of the present invention, it is possible to detect jammed paper without lowering productivity.

1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the invention; FIG. 3 is a diagram showing a schematic configuration of a media sensor (smoothness measuring unit); FIG. 3 is a diagram showing a schematic configuration of a media sensor (paper thickness measuring section); FIG. It is a figure which shows the setting screen of user setting mode and automatic setting mode. FIG. 10 is a diagram showing a pre-purge operation when paper 1 jams during execution of a job in which all recording papers are fed from the same paper feed tray; FIG. 10 is a diagram showing an auto-purge operation when paper No. 3 jams during execution of a job in which all recording papers are fed from the same paper feed tray; FIG. 10 is a diagram showing a pre-purge operation when the first sheet jams during execution of a job in which sheets are mixedly fed from a plurality of paper feed trays; FIG. 10 is a diagram showing an example of feeding new recording paper for media detection by piggybacking on a pre-purge operation when a jam occurs during execution of a job in which all recording paper is fed from the same paper feed tray; . FIG. 10 is a diagram showing an example of feeding new recording paper for medium detection by piggybacking on a pre-purge operation when a jam occurs during execution of a job in which mixed paper is fed from a plurality of paper feed trays. FIG. 10 is a diagram showing an example of controlling the conveying order so as to preferentially discharge a recording sheet detected as a medium in a purge operation; FIG. 10 is a diagram showing an example of a case where there is no need to preferentially discharge the recording paper for which media are detected in the purge operation; FIG. 10 is a diagram showing an example of a jam code list; FIG. 5 is a diagram showing a time chart of operations after occurrence of a jam in the image forming apparatus according to the embodiment of the present invention; FIG. 10 is a diagram showing a time chart of operations when media detection is performed after a printable state has been established after a jam has been cleared; 4 is a flowchart showing processing performed by the image forming apparatus when a jam occurs; FIG. 16 is a flowchart showing a continuation of FIG. 15; FIG. 10 is a flow chart showing a process for determining whether or not it is necessary to preferentially convey a recording sheet whose medium is to be detected; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 3 according to an embodiment of the invention. The image forming apparatus 3 includes a paper feed unit 5 having a plurality of paper feed trays (paper feed trays 1 to 3), a main body 10, and a post-processing unit . The paper feed unit 5 feeds the recording paper stored in the paper feed trays 1 to 3 and feeds and conveys it toward the main body 10 . The main unit 10 forms an image on the recording paper conveyed from the paper feeding unit 5 and sends it to the post-processing unit 7 in the subsequent stage. The post-processing unit 7 has the function of performing post-processing such as punching, binding, folding, etc. on the recording paper received from the main body 10 and the function of discharging the recording paper received from the main body 10 to the main paper discharge tray 8 or the purge tray 9. fulfill

The image forming apparatus 3 includes a transport section 12 that transports recording paper from the paper feed trays 1 to 3 of the paper feed unit 5 to the main paper discharge tray 8 or the purge tray 9 of the post-processing unit 7 via the main body 10 . The conveying section 12 includes a main path 12a from the paper feeding unit 5 to the main discharge tray 8 and the purge tray 9 of the post-processing unit 7 via the image forming section 11 for forming an image on the recording paper, It has a reversing path 12b for reversing the front and back of the paper. The reversing path 12b branches off from the main path 12a downstream of the fixing device 11c, which will be described later, and joins the main path 12a upstream of the image forming section 11 via a reversing section 12c that reverses the front and back of the recording paper. The transport path 12 includes a transport path having a large number of transport rollers and transport guides, a motor for driving the transport rollers of the transport path, and the like.

The image forming section 11 includes an endless intermediate transfer belt 11a that is looped around, image forming units 11b for C, M, Y, and K colors arranged along the intermediate transfer belt 11a, a fixing device 11c, and the like. be done.

The image forming section 11 superimposes C, M, Y, and K toner images on the intermediate transfer belt 11a by the image forming unit 11b to form a full-color toner image. The toner image formed on the intermediate transfer belt 11 a is transferred at the secondary transfer position D onto the recording paper conveyed from the paper feed unit 5 . The recording paper onto which the toner image has been transferred is pressurized and heated while passing through the downstream fixing device 11c to be fixed on the recording paper. The recording paper exiting the fixing device 11c is conveyed by the conveying section 12 toward the post-processing unit 8 in the subsequent stage. In the case of double-sided printing, the recording paper on which an image has been formed on the front surface by the image forming section 11 is reversed through the reversing path 12b, and then the main path 12a is upstream of the registration section 13 that temporarily stops the recording paper. After an image is formed on the rear surface of the sheet by the image forming section 11 , the sheet is conveyed toward the post-processing unit 7 .

A media sensor 20 is provided on the transport path (main path 12a) in the main body 10 to measure various physical property values of the transported recording paper. Here, the media sensor 20 is provided immediately upstream of the point where the reverse path 12b joins the main path 12a.

The image forming apparatus 3 further includes an operation panel 14 that performs a function of receiving various operations from the user and a function of displaying setting screens/operation screens, device status, warnings, and the like.

The main body 10 of the image forming apparatus 3 also includes a control board 15 that controls the operation of the image forming apparatus 3 . The control board 15 is mainly composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU of the control board 15 performs the functions of the control section 16 and the jam detection section 17 by executing programs. The control unit 16 controls various operations in the image forming apparatus 3 . The jam detector 17 detects paper jams that occur on the transport path of the transport unit 12 . Sensors for detecting jams are provided at various locations along the conveying path, and the jam detector 17 detects the occurrence and release of jams from the output values of these sensors.

2 and 3 show a schematic configuration of the media sensor 20. FIG. The media sensor 20 measures the smoothness, paper thickness, etc. as physical property values of the recording paper. 2 shows a schematic configuration of the smoothness measuring section 21 for measuring the smoothness of the recording paper in the media sensor 20, and FIG. 3 shows a schematic configuration of the paper thickness measuring section 26 for measuring the paper thickness.

A recording sheet to be detected as a medium passes between an upper guide plate 31 and a lower guide plate 32 which are arranged close to each other and form a part of the transport path (main path 12a). The smoothness measuring unit 21 includes a light emitting element 22 that irradiates light toward the recording paper to be measured through a translucent window 33 formed in the upper guide plate 31, and the light emitted from the light emitting element 22 is specularly reflected by the recording paper. A first light receiving element 23 for receiving light through the translucent window 33; It has a pressing portion 25 that presses the recording paper from the back side toward the upper guide plate 31 at a certain location. Here, the light emitting element 22 is an LED (light emitting diode), and the first light receiving element 23 and the second light receiving element 24 are photodiodes.

The pressing portion 25 is provided between the upper guide plate 31 and the lower guide plate 32, and includes a reference reflector 25a having a high reflectivity and having a flat plate shape for pushing up the recording paper from the back side, and a straight plate for moving the reference reflector 25a up and down. It has a dynamic solenoid 25b. The movable iron core of the solenoid 25b passes through a through hole 34 formed in the lower guide plate 32 and is connected to the center of the back surface of the reference reflector 25a to support and move the reference reflector 25a up and down.

The smoothness measuring section 21 of the media sensor 20 detects the smoothness from the relationship between the output value of the first light receiving element 23 and the output value of the second light receiving element 24 . For more accurate detection, it is necessary to keep the distance between the light receiving element sensors 23 and 24 and the recording paper to be measured constant. Therefore, the pressing portion 25 presses the recording paper against the upper guide plate 31 at the location where the translucent window 33 is provided, thereby positioning the recording paper. For measurement by the smoothness measuring unit 21, it is necessary to perform a series of operations such as stop of conveyance→pressing by the pressing unit 25→measurement by the first light receiving element 23 and the second light receiving element 24, and release of pressing. takes a long time to some extent.

In addition, in preparation for measurement, the reflected light of the light emitting element 22 is received by the light receiving elements 23 and 24 while the reference reflector 25a is pressed against the upper guide plate 31 to calibrate the sensor. It is necessary to feed the recording paper after releasing the pressure on 31, and the calibration operation also takes a certain amount of time.

As shown in FIG. 3, the paper thickness measuring unit 26 for measuring the paper thickness includes a pressing plate 27 which is located between the upper guide plate 31 and the lower guide plate 32 and presses the recording paper toward the upper guide plate 31; A line CCD 28 is arranged vertically outside and below the lower guide plate 32, and a motor (not shown) extends downward from the back surface of the pressing plate 27 and passes through a through hole formed in the lower guide plate 32. It comprises a support arm 29 connected to the drive. The supporting arm 29 is provided with a measuring rod 29a protruding sideways across the light receiving surface of the line CCD 28. As shown in FIG.

The pressing plate 27 is driven by the drive unit to move up and down, and the line CCD 28 measures the position of the measuring rod 29a that moves vertically together with the pressing plate 27. As shown in FIG. The paper thickness measuring unit 26 measures the position of the measuring rod 29a when the pressing plate 27 is pressed against the upper guide plate 31 without holding the recording paper, and the position of the pressing plate 27 against the upper guide plate 31 while holding the recording paper. The thickness of the recording paper is detected from the difference from the position of the measuring rod 29a when the measuring rod 29a is pressed.

For measurement by the paper thickness measuring unit 26, a series of operations of stopping the transportation → pressing the pressing plate 27 toward the upper guide plate 31 → measuring the position of the measuring rod 29 a with the line CCD 28 and canceling the pressing by the pressing plate 27 is performed. Since it is necessary to perform the measurement, it takes a long time to some extent.

In preparation for measurement, the pressing plate 27 is pressed against the upper guide plate 31 without holding the recording paper to measure the position of the measuring rod 29a. There is a need.

In this way, the medium detection needs to be performed while the transportation is temporarily stopped, and it takes a long time to some extent. Therefore, depending on the timing of the medium detection, the productivity of the printer decreases. In addition, in order to measure both the smoothness and the paper thickness with the media sensor 20, the total measurement time is required.

Next, the setting of the paper type (recording paper information) in the image forming apparatus 3 will be described. In the image forming apparatus 3, the paper type (including basis weight, paper thickness, recording paper size, etc.) is set for each paper feed tray. When an image is formed on paper, the image is formed by conveying the recording paper under paper conveyance control conditions determined based on the paper type set in the paper feed tray of the paper feed source. The paper transport control conditions include the paper transport speed, the interval between the preceding paper and the succeeding paper, jam detection time margin, transfer current, fixing temperature, and the like.

The image forming apparatus 3 has two setting modes for setting the paper type for each paper feed tray: a user setting mode in which the user manually sets the paper type, and an automatic setting mode based on the physical property values detected by the media sensor 20 . It has an automatic setting mode that automatically sets the paper type.

In a normal print operation, the image forming apparatus 3 does not measure physical property values (media detection) with the media sensor 20 of recording paper fed from a paper feed tray set to the user setting mode. On the other hand, in a normal print operation, the image forming apparatus 3 performs media detection and feeds the recording paper fed from the paper feed tray set to the automatic setting mode if media detection has not yet been performed. Automatically set the paper type for the paper tray. If media detection has been completed, media detection is not performed.

In the user setting mode, media detection is not performed, so the paper transport control conditions can be set and operated from the start of paper feeding, and productivity is improved compared to media detection in the automatic setting mode.

FIG. 4 shows an example of a setting screen 40 for setting a user setting mode and an automatic setting mode for each paper feed tray. The setting screen 40 is provided with a user setting mode selection button 41, an automatic setting mode selection button 42, and an input display field 43 for inputting/displaying setting contents such as paper type for each paper feed tray. be. In FIG. 4, the user setting mode is set for the paper feed tray 1 and the paper feed tray 2, and the information such as the paper type, basis weight, recording paper size, etc. manually set by the user is displayed in the corresponding input display. It is displayed in column 43.

The paper feed tray 3 is set to the automatic setting mode, and information such as paper type, basis weight, recording paper size, etc. determined by the apparatus by media detection is displayed in the corresponding input display field 43 . As for the paper feed tray set to the automatic setting mode and the media detection has not yet been performed, the input display field 43 indicates that the media has not been detected as indicated by the dashed line in FIG. 4 .

Next, a purge operation when a jam occurs in the image forming apparatus 3 will be described. The image forming apparatus 3 detects the jammed paper by taking advantage of the execution of the purge operation after the occurrence of the jam.

FIG. 5 shows the purging operation when a recording sheet (paper No. 1) just before being discharged to the main discharge tray 8 jams during the execution of a job in which all recording sheets are fed from the same paper feed tray. It is a diagram. It should be noted that each recording sheet is numbered sequentially starting from No. 1 in the order in which it was fed.

In the case of FIG. 5, when the image forming apparatus 3 detects the jam of the 1st sheet, the image forming apparatus 3 pre-purges the 2nd to 6th sheets upstream of the 1st sheet to the purge tray 9 in order before stopping the conveyance. take action. At this time, the media is detected for the No. 5 paper located closest to the media sensor 20 on the upstream side of the media sensor 20, and the paper type is automatically set for the paper feed tray as the paper feed source based on the detection result. In subsequent recovery printing, paper transport control conditions are set based on this paper type. As a result, recurrence of jam is prevented.

In this way, media detection for jammed paper (recording paper fed from the same paper tray as the jammed paper) is performed by piggybacking on the pre-purge operation, eliminating the need for media detection during recovery printing. It is possible to prevent a decrease in productivity due to detection.

FIG. 6 is a diagram showing a purge operation when paper No. 3 jams during execution of a job in which all recording papers are fed from the same paper feed tray. The 1st and 2nd sheets are on the reversing path 12b. In this case, first, the user is asked to remove the jammed paper (paper No. 3). When the image forming apparatus 3 detects that the No. 3 sheet has been removed, the image forming apparatus 3 performs an auto-purge operation to sequentially discharge the other recording sheets on the conveying path to the purge tray 9 . At this time, the media is detected for No. 5 paper, which is closest to the media sensor 20 on the upstream side of the media sensor 20, and based on the detection result, the paper type is automatically selected for the paper feed tray from which the jammed paper is fed. set. In subsequent recovery printing, paper transport control conditions are set based on this paper type. As a result, recurrence of jam is prevented.

In this way, since media detection for jammed paper is performed by taking advantage of the auto-purge operation, there is no need to perform media detection during recovery printing, and it is possible to prevent productivity from deteriorating due to media detection for jammed paper.

FIG. 7 is a diagram showing the purging operation when a recording sheet (paper No. 1) just before being discharged to the main discharge tray 8 jams during execution of a job in which mixed feeding is performed from a plurality of paper feed trays. . Here, the 1st, 4th, 6th, and 7th sheets are fed from the paper feed tray 1, and the 2nd, 3rd, and 5th sheets are fed from other paper feed trays (for example, paper feed trays). It is assumed that the sheet is fed from 3). In the drawing, the recording paper fed from the paper feed tray 1 is shown in gray.

In this case, when the image forming apparatus 3 detects the jam of the 1st sheet, the image forming apparatus 3 performs a pre-purge operation to discharge the 2nd to 7th sheets upstream of the 1st sheet to the purge tray 9 before stopping the conveyance. . At this time, among the recording papers fed from the same paper feed tray as the jammed paper No. 1, the No. 6 paper located closest to the media sensor 20 on the upstream side of the media sensor 20 is media-detected. The paper type is automatically set for the paper feed tray 1 based on the result. After setting, the purging operation is performed on the 6th and 7th sheets under the paper transport control conditions based on the newly set paper type. As a result, the probability of re-jam occurrence during the purge operation can be reduced. In recovery printing, for the recording paper fed from the paper feed tray 1, paper transport control conditions are set based on the new paper type automatically set for the paper feed tray 1. FIG.

FIG. 8 shows an example of feeding new recording paper for media detection by piggybacking on the pre-purge operation. In the example of FIG. 8, during the execution of a job that feeds all the recording sheets from the same paper tray (paper tray 3), the recording sheet (sheet 1) just before being discharged to the main paper output tray 8 is Indicates if jammed. In the figure, the unfed recording paper (No. 5 paper) is indicated by a dashed line.

In this case, the 2nd to 4th sheets upstream from the 1st sheet can be discharged to the purge tray 9 and pre-purged, but all the remaining sheets in the machine (2nd to 4th sheets) are downstream from the media sensor 20. media cannot be detected. Therefore, the No. 5 paper is newly fed from the same paper feed tray 3 as the No. 1 paper, and the medium of the No. 5 paper that is transported by piggybacking on the pre-purge operation is detected. to automatically set the paper type. In subsequent recovery printing, paper transport control conditions are set based on this automatically set paper type. This prevents another jam from occurring.

In this way, when there is no remaining paper that can be detected as media, new paper is fed from the same paper feed tray as the jammed paper during the purge operation, and this recording paper is detected as media. It is no longer necessary to detect the media inside, and it is possible to prevent the decrease in productivity due to media detection related to jammed paper.

FIG. 9 shows an example of feeding new recording paper for media detection by piggybacking on the pre-purge operation when a jam occurs during execution of a job in which mixed paper is fed from a plurality of paper feed trays. . In the example of FIG. 9, the 1st and 4th sheets are fed from the paper feed tray 1, and the 2nd, 3rd, 5th and 6th sheets are fed from the paper feed tray 3. do. In the drawing, the recording paper fed from the paper feed tray 1 is shown in gray. The unfed recording paper (7th paper) is indicated by a dashed line.

In this case, the 5th and 6th sheets of the remaining paper in the machine are located upstream of the media sensor 20 and can be detected as media. There is no recording paper to be media-detected inside. Therefore, the 7th paper is newly fed from the same paper feed tray 3 as the 1st paper, and the media of the 7th paper that is transported by piggybacking on the pre-purge operation is detected. to automatically set the paper type. In subsequent recovery printing, paper transport control conditions are set based on this paper type. This prevents another jam from occurring.

In this way, if there is no remaining paper that can be detected from the same paper feed source as the jammed paper in the machine, new paper is fed from the same paper feed tray as the jammed paper during the purge operation and this recording paper is used. Since media detection is performed, there is no need to perform media detection during recovery printing, and it is possible to prevent productivity from deteriorating due to media detection related to jammed paper.

FIG. 10 shows an example of controlling the conveying order so as to preferentially discharge the recording paper for which the medium is detected in the purge operation. In the example of FIG. 10 , paper No. 3 is jammed, paper No. 1 and paper No. 2 are on the reverse path 12 b, and paper No. 4 and paper No. 5 remain upstream of the media sensor 20 . It is assumed that the 1st, 3rd, and 4th sheets are the recording sheets fed from the paper feed tray 1, and the 2nd and 5th sheets are the recording sheets fed from the paper feed tray 3. .

In this case, the order of transportation after the user removes the third sheet is as follows:
(a) purging in order of sheet 1, sheet 2, sheet 4, sheet 5;
(b) purging in order of sheet 4, sheet 5, sheet 1, sheet 2;
There is In the case of (b) above, the paper transport control conditions are updated based on the paper type obtained by detecting the paper No. 4, which has the same paper source as the jammed paper. Since the paper can be purged, the probability of jamming during the purging operation can be reduced. On the other hand, in the case of (a) above, since the jammed paper and the 1st paper from the same paper feed source are purged before updating the paper transport control conditions based on the paper type obtained by detecting the 4th paper as the media, The jam occurrence probability during the purging operation of the first sheet is higher than in case (b).

Therefore, in the present invention, the probability of jam recurrence during the purge operation is reduced by controlling the transport order so that the recording paper whose medium is detected is discharged preferentially.

Note that, as shown in FIG. 11, the paper feed source (paper feed tray 3) of the remaining paper (paper No. 1 and paper No. 2) upstream of the media sensor 20 is the paper feed source (paper feed tray 3) of the jammed paper (paper No. 3). If it is different from the paper tray 1), the media detection result for the 4th paper does not affect the paper transport control conditions for the 1st and 2nd papers. , the second sheet may be ejected. It is preferable that each recording paper is discharged to the purge tray 9 in the order of paper feeding.

Next, a case will be described in which whether or not media detection is to be performed in accordance with the purge operation after the occurrence of a jam is determined according to the type of jam.

There are various causes for the occurrence of jams, and there are cases where misidentification of the paper type is not the cause. For example, jams in a post-processing device (finisher) are often caused by static electricity of paper sticking to a member, and are not due to misidentification of the paper type. Also, the control jam is caused by the detection of a software logic error while the recording paper is stopped and waiting in the machine, and is not caused by misidentification of the paper type.

Therefore, for a jam that is clearly not caused by misidentification of the paper type, control is performed so that the medium is not detected when the purge operation is performed. Here, since the jam code is numbered according to the cause of the jam, as shown in FIG. When a jam occurs, the jam code corresponding to the jam is used to refer to this list to determine whether media detection is necessary. This saves processing time by avoiding unnecessary media detection during the purge operation.

FIG. 13 is a time chart showing the operation of the image forming apparatus 3 according to the embodiment of the invention after a jam occurs. After the jam occurs, the device stops after the shutdown operation. Prepurge is performed during the shutdown operation. After the jam is cleared, the apparatus is put into a printable state through a start-up operation. Autopurge is performed during this start-up operation. In the present invention, the media is detected by piggybacking on the pre-purge operation and the auto-purge operation (the recording paper conveyed when the purge operation is executed is detected). Recovery printing can be started immediately.

FIG. 14 is a time chart showing the operation when the media is detected after the jam is cleared and the printing becomes possible. Conventionally, as shown in FIG. 14, the recording paper conveyed in recovery printing is detected as a medium. It can be seen that the image forming apparatus 3 of the present invention shown in FIG. 13 has improved productivity compared to the conventional operation shown in FIG.

15 and 16 are flow charts showing processing performed by the image forming apparatus 3 when a jam occurs. When the jam detection unit 17 of the image forming apparatus 3 detects the occurrence of a jam (step S101; Yes), the control unit 16 sets the paper type setting mode for the paper feed tray as the paper feed source of the jammed paper to the user setting mode. It is checked whether it is in the automatic setting mode (step S102). If the paper feed tray from which jammed paper is fed is set to the automatic setting mode (step S102; automatic), a normal purge operation without medium detection is executed (step S105), and this process is terminated. finish.

If the paper feed tray from which the jammed paper is fed is set to the user setting mode (step S102; manual), the jam code is used to determine whether or not the cause of the jam requires media detection. is determined by referring to the list of (step S103). If the cause of the current jam does not require media detection (step S103; No), a normal purge operation without media detection is executed (step S105), and this processing ends.

If the cause of the current jam requires media detection (step S103; Yes), it is checked whether the jammed paper has already been detected (step S104). When media detection is performed, information indicating that the media has been detected is registered in association with the paper feed tray from which the recording paper for which the media has been detected is fed. (See FIG. 16, step S113), and the determination in step S104 is made based on this information. If the jammed paper has been detected as the medium (step S104; Yes), a normal purge operation without medium detection is executed (step S105), and the process ends.

If the jammed paper has not been media-detected (step S104; No), it is determined whether there is purge paper fed from the same paper feed tray as the jammed paper in the transport path upstream of the media sensor 20 ( step S106). If the purge paper fed from the same paper feed tray as the jammed paper exists in the transport path upstream of the media sensor 20 (step S106; Yes), the process proceeds to step S108.

If there is no purge paper fed from the same paper feed tray as the jammed paper in the transport path upstream of the media sensor 20, then a new sheet of recording paper is fed from the same paper feed tray as the paper feed source of the jammed paper. Paper is fed (step S107), and the process proceeds to step S108.

In step S108, the recording paper (this will be referred to as recording paper A) to be media-detected is specified. Specifically, the recording paper A is specified as the recording paper A that is the same as the paper feed source of the jammed paper and is upstream of the media sensor 20 and closest to the media sensor 20 .

Next, the conveying order in the purge operation is determined so that the recording sheet A is preferentially discharged (step S109). For example, in the state shown in FIG. 10, the conveying order in the purge operation is determined so that the 4th, 5th, 1st and 2nd sheets are discharged in this order.

Next, the purge operation is started in the conveying order determined in step S109 (step S110). When the media detection of the recording paper A is completed (step S111; Yes), the paper type is determined based on the result of the media detection, and the determined paper type is placed in the paper feed tray (recording tray) of the jammed paper feed source. (same as the paper feed source of paper A)) and automatically set (step S112).

Next, the paper feed tray from which the jammed paper is fed is set to media detection (step S113), and the paper transport control condition for the recording paper fed from the same paper feed tray as the jammed paper is set to the paper feed tray. is changed to a value based on the automatically set paper type (step S114). The processes of steps S112 to S114 are executed immediately after detecting the medium of the recording paper A, and are reflected in the subsequent transportation (including the transportation of the recording paper A) during the purge operation.

Note that the recording paper to be media-detected is only the recording paper fed from the same paper feed tray as the jammed paper (recording paper A in the above example), and other recording papers are not media-detected.

As described above, in the image forming apparatus 3 according to the present invention, when a jam occurs, by taking advantage of the purging operation, there is no remaining paper fed from the same paper feed tray as the jammed paper or no corresponding remaining paper. In some cases, recording paper that is newly fed from the same paper feed tray as the jammed paper is detected as media, so media detection for jammed paper can be performed without lowering productivity, which reduces productivity. Recovery printing can be performed without

In addition, since the recording paper from the same feeding source as the jammed paper is detected at an early stage and the paper transport control conditions are immediately switched based on the detected paper type, the jam recurrence probability during the purge operation can be reduced.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to those shown in the embodiments, and modifications and additions may be made without departing from the scope of the present invention. is also included in the present invention.

In the embodiment, the conveying order in the purge operation is determined so that the recording paper A whose medium is detected is always discharged with priority (FIG. 16, step S109). 11, and the recording paper A may be preferentially ejected only in the case of the state shown in FIG. FIG. 17 shows processing related to the determination. It is determined whether or not the purge paper fed from the same paper feed tray as the jammed paper is downstream of the media sensor 20 (step S201). 20 (step S201; Yes), the transport order is determined so that the recording paper A whose medium is detected is discharged preferentially (step S202). On the other hand, if there is no purge paper fed from the same paper feed tray as the jammed paper downstream of the media sensor 20 (step S201; No), the transport order is changed so that the paper is discharged in order from the upstream (discharged in order of paper feed). Determine (step S203).

REFERENCE SIGNS LIST 3: Image forming apparatus 5: Paper feed unit 7: Post-processing unit 8: Main paper discharge tray 9: Purge tray 10: Main body 11: Image forming section 11a: Intermediate transfer belt 11b: Image forming unit 11c: Fixing device 12: Conveyance Part 12a... Main path 12b... Reversing path 12c... Reversing part 13... Registration part 14... Operation panel 15... Control board 16... Control part 17... Jam detection part 20... Media sensor 21... Smoothness measurement part 22... Light emitting element 23... First light-receiving element 24 Second light-receiving element 25 Pressing part 25a Reference reflector 25b Solenoid 26 Paper thickness measuring part 27 Pressing plate 28 Line CCD
29... Support arm 29a... Measuring rod 31... Upper guide plate 32... Lower guide plate 33... Translucent window 34... Through hole 40... Setting screen 41... User setting mode selection button 42... Automatic setting mode selection button 43... Input Display field

Claims (8)

a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
When the jam detection unit detects a jam of the recording paper, the conveying unit is caused to perform a purge operation to convey the recording paper remaining in the conveying path to a predetermined paper discharge destination, and the recording paper remaining in the conveying path is controlled. a control unit that causes the media sensor to measure physical property values of the paper when the purge operation is executed;
An image forming apparatus comprising: a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The image forming apparatus according to claim 1, wherein, if the jammed recording paper has been measured by the media sensor, the control unit does not perform the measurement when the purge operation is performed. a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit causes the media sensor to measure only recording paper fed from the same paper feed tray as the jammed recording paper among the recording papers transported during the execution of the purge operation. image forming device. When the recording paper that caused the jam and the recording paper from the same paper feed tray as the paper feed source do not remain in the conveying path upstream of the media sensor, the control unit clears the jam during execution of the purge operation. 4. The image forming apparatus according to claim 3, wherein the recording paper is fed from the same paper feed tray as the paper feeding source of the raised recording paper, and the recording paper is measured by the media sensor. a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit is characterized in that the control unit controls the transport order of the recording paper to be transported when the purge operation is performed so that the recording paper to be measured by the media sensor is preferentially transported to the discharge destination . Image forming device. a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
The control unit determines whether or not to cause the media sensor to measure physical property values of the recording paper conveyed during execution of the purge operation, according to the type of jam detected by the jam detection unit. image forming apparatus. a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
A user setting mode in which the user sets recording paper information to be linked to a paper feed tray, and a media sensor that measures the recording paper fed from the paper feed tray during image formation and transported, and based on the measurement results, the paper is fed. It has an automatic setting mode that automatically sets the recording paper information linked to the paper tray,
The image forming apparatus, wherein the control unit sets conditions for conveying recording paper fed from the paper feed tray based on recording paper information linked to the paper feed tray. a conveying unit that feeds and conveys recording paper from a paper feed tray;
an image forming unit that forms an image on the recording paper conveyed by the conveying unit;
a media sensor for measuring physical property values of the recording paper being conveyed on the conveying path of the conveying unit;
a jam detection unit that detects a jam of the recording paper conveyed by the conveying unit;
causing the transport unit to perform a purge operation for transporting the recording paper remaining in the transport path to a predetermined discharge destination when the jam detection unit detects a jam of the recording paper, and transporting the recording paper when the purge operation is executed; a control unit that causes the media sensor to measure the physical property values of the recording paper;
has
Based on the recording paper information linked to the paper feeding tray, the control unit sets the conveying conditions of the recording paper fed from the paper feeding tray and conveyed when the purge operation is executed. Recording paper information obtained by measuring, with the media sensor, the jammed recording paper and the recording paper having the same paper feed tray as the paper feed source is used as the paper feed source of the jammed recording paper. An image forming apparatus characterized by being tied to a paper feed tray.

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