JP2022088632A - Image forming apparatus and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: when double-sided printing is performed on pre-punched paper, an inverting roller 62 of a switchback system for inverting the front and back of a sheet is caught in holes in the sheet, and the inverting roller 62 slips when the inverting roller starts reverse rotation, which delays arrival of the sheet to a double-sided path sensor 602, which is determined as paper jam.

SOLUTION: When double-sided printing is performed on pre-punched paper, a conveyance interval of sheets to be conveyed to an inverting unit is made longer than that in the case where double-sided printing is performed on paper other than the pre-punched paper.

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and a control method thereof.

In recent years, image forming devices such as copiers, printers, and facsimiles have been commercialized for double-sided printing that prints on the front and back of paper because of the user's need to save paper for printing.

As a means for inverting the front and back of paper for double-sided printing, a switchback method using a pair of transport rollers capable of forward and reverse rotation is widely used because the device can be miniaturized with a simple configuration.

Patent No. 3110432

However, in the switchback type apparatus described in Patent Document 1, there are the following problems in the case of double-sided printing on pre-punched paper having holes in advance in order to bind the paper to a file, a binder, or the like. It is a switchback roller (hereinafter referred to as a reversing roller) that reverses the paper during double-sided printing. At the start of reversing after stopping, the position of the hole in the pre-punched paper and the reversing roller overlap, and the paper rolls as expected. Not transported. That is, the reversing roller slips at the hole, resulting in a paper jam (hereinafter referred to as jam). As a result, there is a problem that the deliverable of double-sided printing cannot be obtained.

An object of the present invention is to prevent a paper jam from being determined when the front and back of the paper are reversed by switchback.

In order to solve the above problems, the image forming apparatus of the present invention is an image forming apparatus for printing an image on paper, in order to reverse the front and back of the conveying means for conveying the paper and the paper conveyed by the conveying means. A reversing means for switching back and reversing the paper, a paper sensor arranged downstream of the reversing means in the transport direction after the paper is flipped by the reversing means, and a paper sensor for detecting the flipped paper, and the reversing. It is determined whether or not the paper inverted by the means has reached the paper sensor within a predetermined time, and if the jam is determined, the control means for stopping the paper transport and the predetermined time are made longer than usual. It has a setting means for setting a predetermined mode, and the control means is characterized in that a jam is determined based on the setting of the setting means.

According to the present invention, it is possible to prevent a paper jam from being determined when the front and back of the paper are reversed by switchback.

It is sectional drawing of the image forming apparatus. It is a block diagram which shows the control system of an image forming apparatus. It is a figure which shows the structure of print information. It is a flowchart of mode setting for pre-punched paper. It is a flowchart which shows the print control. It is a figure which shows the setting screen for the pre-punch paper. It is explanatory drawing of the mode setting contents for pre-punch paper.

Hereinafter, embodiments of the present invention will be described.

First, the overall configuration of the image forming apparatus according to the embodiment of the present invention will be outlined with reference to FIG.

FIG. 1 is an overall configuration explanatory view of an electrophotographic printer 1 (hereinafter referred to as a printer), which is a form of an image forming apparatus according to the present embodiment.

The printer 1 has an image forming unit 3 having an image carrier 31 rotating at a constant speed and a developer 32. The surface of the image carrier 31 is uniformly charged by a charger (not shown), exposed to laser light modulated according to the image data, and an electrostatic latent image is formed on the image carrier 31. The electrostatic latent image is developed into a toner image by the developer 32.

A cassette 100, which is a paper feeding unit for feeding paper P, is arranged in the printer 1. Further, a manual feed tray 200 is arranged in the printer 1.

The cassette 100 has a cassette having a function of identifying a paper size to be accommodated, a cassette paper feed roller 101 for feeding paper P, and a cassette paper presence / absence sensor 103 for detecting the presence / absence of paper in the cassette.

The manual feed tray 200 has a manual feed tray paper feed roller 201 for feeding paper P, and a manual feed tray paper presence / absence sensor 203 for detecting the presence / absence of paper on the tray.

The paper P stored in the cassette 100 is separated and fed one by one by the cassette paper feed roller 101 and the separating means (not shown) and sent out. The paper P sent out from the cassette 100 is conveyed by the cassette transfer roller 102 and the transfer roller 10 and is sent to the registration roller 20.

Further, the paper P placed on the manual feed tray 200 is separately fed and fed one by one by the manual feed tray paper feed roller 201 and the separating means (not shown).

The paper P sent out from the manual feed tray 200 is conveyed by the manual feed tray transfer roller 202 and sent to the registration roller 20.

The paper P separated and fed from the cassette 100 or the manual feed tray 200 is conveyed to the transfer unit T by the registration roller 20 at the timing synchronized with the toner image developed on the image carrier 31.

In the transfer unit T, the toner image is transferred to the paper P by the action of the transfer bias applied to the transfer roller 33. The paper P on which the toner image is transferred is conveyed to the fixing device 4, so that the image is fixed on the paper P. In the case of single-sided printing, the paper P is conveyed in the direction of the paper ejection unit 5 by the action of the fixing transport roller 41 and the branch flapper 51, and is loaded on the paper ejection unit 5 in page order by the paper ejection roller 52.

In the case of double-sided printing, the paper P for which the image formation on the first side is completed is conveyed in the direction of the double-sided transfer portion 6 by the action of the fixing transfer roller 41 and the branch flapper 51, and then the paper is conveyed via the double-sided transfer roller 61. It is conveyed to the reversing roller 62.

The reversing roller 62 rotates in the forward direction to convey the paper P, but when the rear end of the paper P reaches a predetermined reversing position R, the reversing roller 62 stops, and then the reversing roller 62 rotates in the reverse direction. That is, the front and back of the paper P are reversed by the switchback method. The fact that the paper P has reached the reversing position R is determined by the fact that the paper P has been conveyed by a predetermined distance after the rear end of the paper P is detected by the reversing sensor 601.

The paper P switched back by the inverting roller 62 is conveyed to the double-sided pass roller 63 side, and is conveyed to the re-feeding roller 64 by the double-sided pass roller 63.

The paper P is conveyed by the re-feed roller 64, and when the tip of the paper P reaches the re-feed standby position S, the re-feed roller 64 stops. The fact that the paper P has reached the re-feeding standby position S is determined by the fact that the re-feeding roller 65 has conveyed the paper by a predetermined distance after the re-feeding sensor 65 detects the tip of the paper P.

At the timing when printing on the second side becomes possible, the drive of the refeed roller 64 is restarted, the paper P is conveyed to the registration roller 20, and the image formation on the second side is executed in the same manner as on the first side.

Then, the paper P for which the fixing of the toner image on the second surface is completed is conveyed in the direction of the paper ejection portion 5 by the action of the fixing and conveying roller 41 and the branch flapper 51, and is ejected to the paper ejection portion 5 by the paper ejection roller 52. ..

Next, the electrical control block of the printer 1 of FIG. 1 will be described with reference to FIG.

The CPU 1000 as a control unit communicates image data sent from an external device 1100 such as a personal computer via an I / F 260 composed of USB and LAN. Then, the operation of the printer 1 is controlled based on the content of the print job received from the external device 1100.

FIG. 3 shows the print information included in the print job received from the external device 1100. This print information is stored in the RAM 1002 and used for print control by the CPU 1000.

ID number 401 is information for identifying each print job. The paper size 402 is information representing the length and width dimensions of the paper used in the print job, and is specified in millimeters. The paper feed port 403 is information for designating a paper feed port for feeding paper. The paper ejection port 404 is information for designating the paper ejection port from which the printed paper is ejected. The print mode 405 is prepared for designating control according to the basis weight (g / m ² ) of the paper or the type of the paper, and includes a thin paper mode, a plain paper mode, a thick paper mode, an AUTO mode, and the like. The single-sided / double-sided printing 406 is designated information for single-sided / double-sided printing set by the external device 1100 or the operation unit 250.

Returning to the description of FIG. 2, the ROM 1001 contains a program executed by the CPU 1000 to control the printer. Further, the RAM 1002 is used for reading and writing processing data when controlling the printer.

The print control unit 1010 performs a series of high-voltage control such as charging, development, and transfer, optical system control such as a scanner motor and a laser beam, and fixing control according to the instruction of the CPU 1000. Further, the print control unit 1010 controls these loads and detects the operating state of the loads. The CPU 1000 determines the failure of each load according to a predetermined condition from the operating state detected by the print unit 1010.

The sensor group 610 of the transport path includes a paper sensor arranged in the transport path such as an inversion sensor 601 and a refeed sensor 65. The CPU 1000 monitors the paper transport state by these paper sensors.

The operation unit 250 is used to display print information, printing progress status, and the like, and to make various printer settings by the user.

Next, the mode setting and the control at the time of printing of this embodiment will be described with reference to FIGS. 4 and 5. 4 and 5 are flowcharts of processes executed by the CPU 1000. This flowchart relates to an operation when double-sided printing is performed on pre-punched paper in the front-back inversion control of paper by a switchback method.

Before going into the explanation of the flowchart, the reason why the control shown in FIGS. 4 and 5 is necessary when the pre-punched paper is printed on both sides will be described.

Pre-punched paper is paper that has holes for filing in advance in order to bind the paper to a file, binder, or the like. For example, 22 holes for a computer binder, 26 holes for loose-leaf (paper size B5), 30 holes (paper size A4), and the like are generally known.

In the present embodiment, it is premised that the paper transport direction when printing pre-punched paper is the rear end side of the paper transport direction.

When pre-punched paper is fed from a cassette or the like so that the holes are on the tip side in the transport direction, the paper feed roller may slip at the holes or the paper tip may bend during paper feed.

Further, when the pre-punched paper is conveyed so that the arrangement of the holes is parallel to the conveying direction, the fixing temperature on the perforated side becomes too high, which may cause downtime.

Therefore, the pre-punched paper is fed from the cassette or the like so that the holes are on the rear end side in the transport direction.

When the pre-punched paper is conveyed with the holes on the rear end side, in the switchback system configuration, when the forward rotation of the reversing roller 62 is stopped, the reversing roller 62 is stopped while holding the rear end side of the paper. Here, the reversing roller 62 may stop in a state of being hooked on the hole of the pre-punched paper, rotate in the reverse direction of the reversing roller 62, and slip when starting the transfer to the double-sided transfer section 6.

Here, the double-sided pass sensor 602 arranged downstream of the reversing roller 62 (conveying direction after reversing) detects jam on the pre-punched paper that has been flipped back. If the reversing roller 62 slips at the start of reverse rotation and the paper does not reach the double-sided pass sensor 602 within a predetermined time (transport time without transfer delay + jam margin time Tm), it is determined to be jam. Further, when the productivity of double-sided printing is high, if the next paper is conveyed while the reversing roller 62 is slipping, the reversing roller 62 starts forward rotation in order to convey the paper. , The slipped paper is pushed out of the reversing roller 62. As a result, it is determined that the jam exceeds the jam merge time Tm of the re-feed sensor 65.

For the jam determination at the time of switchback reversal, the refeed sensor 65 may be used instead of the double-sided pass sensor 602.

In the present embodiment, as a countermeasure against slipping of the reversing roller 62, a pre-punch paper mode for extending the jam margin can be set. Hereinafter, specific control will be described.

FIG. 4 is a flowchart relating to the setting of the pre-punch paper mode as a predetermined mode in the case of double-sided printing on the pre-punch paper.

When the power of the printer 1 is turned on, the CPU 1000 executes the control program stored in the ROM 1001. In the standby state after the printer is started (hereinafter referred to as the standby state), the CPU 1000 monitors whether the pre-punch paper mode screen shown in FIG. 6 is selected in the operation unit 250.

When the CPU 1000 determines that the pre-punch paper mode screen has been selected, the flowchart for setting the pre-punch paper mode in FIG. 4 is started. When the processing of the flowchart of FIG. 4 is completed, the printer 1 returns to the standby state.

When the CPU 1000 receives the print information from the external device 1100 via the I / F 260 in the standby state, the print control process shown in FIG. 5 is started by the CPU 1000. When the flowchart processing of FIG. 5 is completed, the printer 1 is put into the standby state again.

In S101, when the user selects one of the settings on the pre-punch paper mode screen of FIG. 6 displayed on the operation unit 250 by the user's operation, the CPU 1000 stores the selected setting information in the RAM 1002.

The user can select five settings of OFF, mode 1, mode 2, mode 3, and mode 4. OFF (mode 0) is a normal mode, and is not particularly set for pre-punched paper. That is, the jam margin at the time of switchback for double-sided printing by the reversing roller 62 is the same as that of non-pre-punched paper. Modes 1 to 4 are pre-punch paper modes applied when double-sided printing of pre-punch paper is performed.

The setting by the pre-punch paper mode screen is set as the initial setting information of the printer 1, and the mode once set is maintained until it is changed to another mode.

The details of each mode will be described later.

In S102, the CPU 1000 determines whether or not the "execution" key 252 is pressed on the pre-punch paper mode screen, and waits until the "execution" key 252 is pressed.

If the CPU 1000 determines in S102 that the "execute" key 252 is pressed, the CPU 1000 proceeds to S103.

In S103, the CPU 1000 hides the setting screen displayed on the operation unit 250 and ends the setting process.

Next, the control at the time of printing will be described with reference to the flowchart of FIG. In FIG. 5, when the CPU 1000 receives the print information from the external device 1100 via the I / F 260, the processing of the flowchart is started. The CPU 1000 stores the print information acquired from the external device 1100 in the RAM 1002. Here, an example of printing on B5 size pre-punched paper is shown.

In S111, the CPU 1000 reads the setting information selected in S101 of FIG. 4 from the RAM 1002, and determines whether the pre-punch paper mode is mode 1 to mode 4 or is off.

When any of modes 1 to 4 which is the pre-punch paper mode is set, the CPU 1000 changes the jam margin time Tm from T1 to T4 according to the pre-punch paper mode in S112.

Here, the details of the pre-punch paper mode will be described with reference to FIG. 7.

FIG. 7 shows the jam margin time for each mode and the number of print pages (PPM: Print Per Minute) that can be printed in one minute. Mode 0 is a normal mode, and the jam margin time is T0. The initial state is set to mode 0.

Modes 1 to 4 are pre-punch paper modes applied when double-sided printing is performed on pre-punch paper. The magnitude relationship of the jam margin time in each pre-punch paper mode is T1 <T2 <T3 <T4. Since the jam margin time increases in the order of mode 1 → mode 2 → mode 3 → mode 4, the improvement effect on double-sided printing of pre-punched paper becomes high.

When mode 1 is selected, the CPU 1000 changes the jam margin time Tm of the double-sided pass sensor 602 to a value T1 that is longer than the default value. The productivity at this time is 40 PPM, which is the same as that at the time of OFF. That is, the jam margin Tm increases within the range in which the productivity does not decrease.

When mode 2 is selected, the CPU 1000 changes the jam margin time Tm of the double-sided pass sensor 602 to T2. The productivity at this time is 30 PPM.

When mode 3 is selected, the CPU 1000 changes the jam margin time Tm of the double-sided pass sensor 602 to T3. The productivity at this time is 25 PPM.

When the mode 4 is selected, the CPU 1000 changes the jam margin time Tm of the double-sided pass sensor 602 to T4 and changes the paper feed timing of the next paper. Specifically, the reversing roller 62 is rotated in the reverse direction, and after it is detected that the switchback inverted paper has reached the double-sided pass sensor 602, the next paper is fed from the cassette 100 or the manual feed tray 200. The productivity at this time is 10 PPM.

In S111, when the setting mode is mode 0, the CPU 1000 sets the jam margin time Tm to the initial value T0 in S120.

When the jam margin time Tm is set, in S113, the CPU 1000 reads the print information shown in FIG. 4 from the RAM 1002, controls the print control unit 1010 based on the read print information, and executes single-sided printing or double-sided printing. do. The CPU 1000 controls the paper feed interval (conveyance interval) according to the PPM values corresponding to the set modes (0 to 4).

In S114, the CPU 1000 determines whether or not the first side of the double-sided printing is executed based on the information of the single-sided / double-sided printing 406 included in the print information from the RAM 1002. When the first side of double-sided printing is executed in S114, the CPU 1000 determines jam at the time of switchback inversion in S115.

Specifically, the CPU 1000 determines whether or not Tx <Ta + Tm. Here, Tx is the real time required for the pre-punched paper to reach the double-sided pass sensor 602 after the reversing roller 62 starts the reverse rotation. Ta is a calculated time when there is no transfer delay from the start of reverse rotation of the reversing roller 62 to the arrival of the pre-punched paper on the double-sided pass sensor 602. That is, the real time Tx at which the paper tip reaches the refeed sensor 65 from inversion is compared with the calculated time Ta at which the paper tip reaches the refeed sensor 65 from inversion plus the jam margin time Tm. Then, the jam is judged.

When Tx <Ta + Tm, the CPU 1000 determines that the pre-punched paper has been normally switched back and proceeds to proceed to S116.

In S116, the CPU 1000 determines whether or not the printing of the final page is completed, and if the printing of the final page is not completed, returns to S113 and continues printing. If the printing of the final page is completed, the process ends.

On the other hand, in S114, when it is not the first side printing of double-sided printing, that is, the second side of single-sided printing or double-sided printing, the CPU 1000 does not perform the jam determination at the time of switchback reversal in S115, and proceeds to the process to S116. ..

If Tx <Ta + Tm is not satisfied in S115, the CPU 1000 determines that a jam has occurred at the time of switchback inversion, and stops the printing operation in S121.

Then, in S122, the CPU 1000 waits until the jam processing is completed.

When the CPU 1000 determines that the jam processing is completed, the jam paper recovery setting is set in S123, and the process returns to S113 to continue printing.

As described above, according to the present embodiment, a mode in which the jam margin time is extended is provided in order to print on both sides of the pre-punched paper. Then, by selecting this mode, even if the reversing roller 62 of the double-sided transport unit 6 slips, the reversing drive time of the reversing roller 62 is extended, so that the user can escape from the slipped state. As a result, double-sided printing can be continued without jamming.

In particular, in a miniaturized device, it is difficult to secure a space due to restrictions such as a transport path of the double-sided transport unit 6, and it is considered that the stop position of the paper reversing roller 62 is limited, which is highly effective. You can expect it.

In the present embodiment, double-sided printing of pre-punched paper is described, but the present invention is not limited to this. That is, the above-mentioned control can be applied to double-sided printing of other predetermined types of paper that are easily slipped by the reversing roller.

Further, not only in the case of double-sided printing, but also in the case of single-sided printing, in the configuration in which the front and back sides of the paper are switched back and then ejected to the output tray, the switchback inversion for front-back reversal paper ejection is also described above. Controls can be applied.

Further, depending on the size of the paper in the direction orthogonal to the transport direction, the influence of the slip of the reversing roller may be small at the time of switchback reversing of the pre-punched paper. Therefore, when the paper of a predetermined size is conveyed, the jam margin corresponding to the mode (1 to 4) set in the pre-punch paper mode is set, and if the size is other than the predetermined size, the default value jam margin is set. You may do it.

Further, regardless of the type of paper to be conveyed, a jam margin may be set according to the mode (0 to 4) set on the pre-punch paper mode screen.

6 Double-sided transport unit 62 Inverting roller 63 Double-sided pass roller 250 Operation unit 601 Inverting sensor 602 Double-sided pass sensor 1000 CPU

In order to solve the above problems, the image forming apparatus of the present invention is an image forming apparatus that prints an image on both sides of the paper, and is conveyed by a conveying means for conveying the paper and the conveying means, and the image is transferred to the first surface. It has a reversing means for switching back and reversing the paper in order to reverse the front and back of the printed paper, and a control means for controlling the transport interval of the paper transported to the reversing means by the transporting means. The means means that the transport interval when the type of paper transported by the transport means is pre-punched paper with holes for filing is larger than the transport interval when the paper type is not the pre-punched paper. It is characterized by spreading.
Further, the image forming apparatus of the present invention includes a feeding means for feeding paper, a printing means for printing on the paper fed by the feeding means, and a paper printed on the first surface by the printing means. A reversing means for inverting the front and back of the paper by switching back the paper, and a refeeding method for refeeding the paper toward the printing means so as to print on the second side of the paper whose front and back are reversed by the inverting means. The control means includes a means and a control means for determining the productivity of the number of prints per unit time and executing printing with the determined productivity, and the control means is a pre-punched paper having holes for filing in advance. It is characterized in that the productivity in the case of performing double-sided printing is lower than the said productivity in the case of performing double-sided printing on paper other than the pre-punched paper.

Claims (9)

In an image forming apparatus that prints an image on paper
A transport means for transporting paper and
A reversing means for switching back and reversing the paper in order to reverse the front and back of the paper transported by the transport means.
A paper sensor, which is arranged downstream of the reversing means and for detecting the flipped paper in the transport direction after the paper is flipped by the reversing means,
Jam is determined whether or not the paper inverted by the reversing means has reached the paper sensor within a predetermined time, and if it is determined to be jam, the control means for stopping the paper transfer and the control means.
A setting means for setting a predetermined mode for making the predetermined time longer than usual, and
Have,
The control means is an image forming apparatus, characterized in that jam determination is performed based on the settings of the setting means. The control means is the predetermined time obtained by adding a jam margin to the calculated time when there is no transfer delay, from the time when the reversing means starts to reverse the paper transport direction until the paper reaches the paper sensor. The image forming apparatus according to claim 1, wherein the jam is determined by comparing with the image forming apparatus. The image forming apparatus according to claim 2, wherein the jam margin time is changed according to the setting of the setting means. The image forming apparatus according to any one of claims 1 to 3, wherein the control means changes the paper transport interval by the transport means according to the setting of the setting means. The control means determines jam based on the setting of the setting means when the size of the paper conveyed by the conveying means is a predetermined size, and when the size of the paper is not the predetermined size, the control means determines the jam. The image forming apparatus according to any one of claims 1 to 4, wherein the jam is determined with the predetermined time as a normal time regardless of the setting of the setting means. The control means determines jam based on the setting of the setting means when the type of paper conveyed by the conveying means is a predetermined type, and when the type of the paper is not the predetermined type, the control means said. The image forming apparatus according to any one of claims 1 to 4, wherein the jam is determined with the predetermined time as a normal time regardless of the setting of the setting means. The one according to any one of claims 1 to 4, wherein the control means determines jam based on the setting of the setting means regardless of the type of paper conveyed by the conveying means. Image forming device. The image forming apparatus according to claim 6, wherein the predetermined type of paper is pre-punched paper having holes for filing in advance. In an image forming apparatus that prints on both sides of paper
A flipping means that switches back the paper to flip the front and back of the printed paper on the first side,
A double-sided transfer unit in which the paper inverted by the inversion means is conveyed for printing on the second side, and a double-sided transfer unit.
A paper sensor arranged in the double-sided transport unit for detecting paper,
Jam is determined whether or not the paper inverted by the reversing means has reached the paper sensor within a predetermined time, and if it is determined to be jam, the control means for stopping the paper transfer and the control means.
A setting means for setting a predetermined mode for making the predetermined time longer than usual, and
Have,
The control means is an image forming apparatus, characterized in that jam determination is performed based on the settings of the setting means.

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