JP2006188324A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer paper in the horizontal size (width) from the position of the guide plate that regulates the horizontal direction as in the past, and in the vertical (conveying direction) size as normal paper transport from the manual feed tray. By detecting using the existing sensor in the section from the paper feed position to the registration roller, that is, the conveyance path where the transfer paper comes into contact with the registration roller involved in the position adjustment of the paper leading edge and the image leading edge when transferring the image. Provided is an image forming apparatus that can easily and accurately detect a transfer sheet whose size has become unknown while being stored without requiring the user to measure the transfer sheet size with a ruler or the like.
In an image forming apparatus having a manual feed tray as a paper feed tray, a manual feed tray 19 is designated as the paper feed tray, an image is not transferred to the transfer paper to be fed, and a transfer paper whose transport direction size is unknown. A CPU 1 having a function of executing a mode for detecting the paper size is provided.
[Selection] Figure 1

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer that uses a manual feed tray as a paper feed tray.

Conventionally, in order to enable the use of irregular-size transfer paper and transfer paper of different paper quality and thickness, printing equipment such as copiers and printers have used fixed-size transfer paper contained in a tray. In addition to the output, a manual feed tray for manually supplying the transfer paper is provided (for example, see Patent Document 1).
Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for accurately detecting a recording paper size by arranging a vertical size and horizontal size detection sensor on a manual feed tray. However, it is necessary to install a number of sensors for size detection, and the size of the manual feed tray must be at least the maximum size of the recordable paper, so when using the manual feed tray, It will always take up space.
By using the above-described manual feed tray, it is possible to easily form an image on various types of transfer paper. However, unless the printing apparatus recognizes the size of the transfer paper set on the manual feed tray, a printing error that prevents normal image formation on the transfer paper will occur.
Conventionally, as a method for detecting the size of the transfer paper set in the manual feed tray, a method of arranging a sensor at a position where a specified paper size can be detected, and the horizontal direction, or the horizontal and vertical directions of the transfer paper placed on the manual feed tray are set. Many methods have been proposed in which the size of the transfer paper is detected by moving the regulating guide, and the horizontal or horizontal and vertical sizes of the transfer paper are detected based on the movement position of the guide.
JP-A-8-194416

However, the technique of disposing a sensor at a position where a specified paper size can be detected has a drawback that the transfer paper size cannot be accurately detected when an irregular-size transfer paper is used.
Next, the method of detecting the transfer paper size based on the moving position of the guide is such that when only the guide plate that regulates the horizontal direction of the transfer paper is used, for example, the written image is A3 portrait and the A4 landscape is set on the manual feed tray. The difference between A3 portrait and A4 landscape cannot be detected only with the guide that regulates the lateral direction. If the image is output as it is, a jam will occur due to a paper size error, etc., and after processing such as opening the cover of the printing device and taking out the transfer paper, you must wait until the recovery of the printing device is completed. Disappear.
In addition, when a guide that regulates the horizontal and vertical directions of the transfer paper is used, the setting position of the guide for detecting the vertical size of the transfer paper is a position where the maximum size that can be fed from the manual feed tray can be detected. Since the manual feed tray becomes large and protrudes from a printing apparatus such as a copying machine or a printer, there is a disadvantage that the installation space becomes large.
Accordingly, the first object of the present invention is to detect the horizontal size (width) of the transfer paper based on the movement position of the guide plate that regulates the horizontal direction as in the prior art, while the vertical (conveying direction) size is determined by manual feed. In the normal paper conveyance process from the tray, transfer is performed for transfer paper whose size has become unknown during storage by detecting it using a sensor located in the section from the paper feed position to the registration roller. An object of the present invention is to provide an image forming apparatus that can easily and accurately detect the paper size without requiring the user to measure the paper size with a ruler.
In addition, the second object of the present invention is to make the transfer speed in this transfer paper size detection mode a condition that makes it difficult to damage the transfer paper as much as possible by making it a slow transfer speed applied to thick paper, OHP, etc. If the detection of the vertical size is found in front of the point where the sheet passing operation on the conveyance path can be switched (the reversal / branch point between double-sided conveyance and straight conveyance), the transfer paper is conveyed and stopped on the double-sided conveyance path. It is an object of the present invention to provide an image forming apparatus that can start printing directly from a double-sided conveyance path without notifying the user of the fact that the transfer sheet whose size has been detected is returned to the manual feed tray.
Furthermore, a third object of the present invention is to limit the print modes that can be selected by the user from among the print modes (straight conveyance, reverse conveyance, duplex conveyance) of the printing apparatus depending on the detected vertical size. An object of the present invention is to provide an image forming apparatus that prevents unnecessary jams from occurring.

In order to solve the above problems, the invention described in claim 1 is directed to an image forming unit that forms an image on transfer paper, a transport path that transports the transfer paper, and a manual feed that feeds the transfer paper to the transport path. In the image forming apparatus having a tray, a width direction size detecting unit that detects a width direction size of the transfer paper, and a control unit, the control unit transfers the manually fed transfer when a manual tray is designated. An image is not formed on the paper, and a transfer paper size detection mode in which the conveyance direction size of the transfer paper is detected by the width direction size detection unit is implemented.
According to a second aspect of the present invention, in the first aspect, the width direction size detection unit is provided in the manual feed tray, and the transfer direction size detection unit is disposed on the transfer sheet on the transport path upstream of the image forming unit. Using the sensor, the control means sets the transfer speed of the transfer paper during a period from the start of feeding from the manual feed tray to the completion of size detection to a constant slow transport speed applied to thick paper and OHP. It is characterized by.
According to a third aspect of the present invention, the image forming apparatus according to the first or second aspect further includes a double-sided conveyance path, and the control unit sets the conveyance path to the double-sided conveyance path side in the transfer paper size detection mode. When the transfer sheet size in the passing direction is determined before the transfer sheet reaches a position where the transfer sheet can be switched to, the transfer sheet is conveyed to the double-sided conveyance path.
According to a fourth aspect of the present invention, in the first, second, or third aspect, the control unit is configured to transfer the double-sided paper to the double-sided conveyance path in the transfer paper size detection mode by ending the paper size detection mode. The conveyance of the transfer paper is stopped in the conveyance path.
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the control unit detects the transfer paper size in a state where the transfer paper is stopped in the double-sided conveyance path in the transfer paper size detection mode. When the mode is finished, the outside is informed that the transfer paper whose detection of the transfer paper size has been detected is stopped in the double-sided conveyance path.
According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the control unit stops the transfer paper size detection mode by stopping the transfer paper in the double-sided conveyance path in the transfer paper size detection mode. In this case, the outside is notified that the transfer paper whose detection of the transfer paper size has been detected is in the double-sided conveyance path, and setting for printing after the size detection mode is performed according to the detected conveyance direction size. The print modes that can be selected are limited.

According to the present invention, in the transfer paper size detection mode, by specifying a paper feed tray as a manual feed tray, it is not possible to determine whether or not it can be stored in a normal tray (main body tray, bank, etc.). , The transfer paper size can be detected.
Also, if the detection of the vertical size is found in front of the point where the transfer operation on the transfer path can be switched (the reversal / double-sided transfer and straight transfer branch point), select the detected vertical size and print on the manual feed tray. A vertical size threshold value (recorded in the ROM 3) that restricts possible print modes (straight paper discharge and reverse / double-side paper discharge) is compared.
If reversal and double-sided conveyance are possible, the transfer paper is conveyed and stopped on the double-sided conveyance path side, and notification to that effect is made so that the user does not bother to return the transfer paper whose size has been detected to the manual feed tray. Printing can be started directly from the transport path.
Also, in printing after the transfer paper size detection mode, the user-selectable print mode is limited (straight discharge only or straight / reverse / double-sided discharge) to eliminate unnecessary jam causes. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an image forming apparatus of the present invention. FIG. 2 is a schematic view showing a conveyance path of the image forming apparatus of the present invention.
The block diagram of FIG. 1 and the schematic diagram of FIG. 2 include a CPU 1, a RAM 2, a ROM 3, a paper discharge sensor 5, a reading device 6, a display unit 7, an operation unit 8, a manual feed tray transfer paper width detection device 9, a transfer device 10, A paper transport device 11, a manual feed tray 19, a manual paper feed sensor 30, and an automatic document feeder 35 are shown.
The CPU 1 controls the entire apparatus. By the operation on the operation unit 8, the manual feed tray 19 is designated as the paper feed tray to be used, and the transfer paper size detection mode is further selected. The set information is displayed on the display unit 7.
When the transfer sheet size detection mode operation is started by an operation from the operation unit 8, a slow speed that applies a conveyance speed to cardboard or OHP is adopted based on a control program recorded in the ROM 3, and paper feeding is performed. Be started.
When the paper feeding is started, the CPU 1 first calculates the width size of the transfer paper (not shown) based on the information from the transfer paper width detection device 9. The calculated width size is recorded in the RAM 2. As the transfer paper advances along the conveyance path, it reaches the manual paper feed sensor 30.
The CPU 1 measures the time from when the manual paper feed sensor 30 is turned on to when it is turned off, and the CPU 1 turns off the manual paper feed sensor from on to off when the manual paper feed sensor 30 is turned off. The transfer paper transport direction (vertical) size is calculated from the time (measurement time) required until the transfer time and the transfer paper transport speed.
The calculated vertical size is recorded in the RAM 2. The calculated vertical size is compared with a vertical size threshold value recorded in the ROM 3. This threshold value is determined by the restrictions on the layout of the paper transport path.
When the straight paper discharge, the reverse paper discharge, and the double-side paper discharge are possible as the transport operation by the paper feed from the manual feed tray 19, the straight paper discharge can be operated regardless of the vertical size.

However, for reversal / double-sided paper discharge, the minimum and maximum vertical sizes that can be transported are defined from the layout of the transport path of the image forming apparatus. It becomes the threshold value. That is, it is necessary to measure the vertical size.
Therefore, by comparing the vertical size of the transfer paper recorded in the RAM 2 with the threshold values (minimum value and maximum value of the vertical size that can be transported) recorded in the ROM 3, only straight sheet discharge can be operated. It is possible to determine whether or not any one of straight sheet discharge, reverse sheet discharge, and double-sided sheet discharge operation is possible. This determination result is recorded in the RAM 2.
The display unit 7 clearly indicates to the user whether the transfer sheet whose size has been detected is in the double-sided conveyance path or the discharge port after the vertical size detection operation is completed. Normally, when printing, a transfer image formed by the transfer device 10 is transferred to transfer paper. In the transfer paper size detection mode, image transfer is not performed by the transfer device 10 and is also transferred to transfer paper. Absent.
The present invention relates to an image forming unit (photosensitive member, exposure unit, developing unit, transfer unit, etc.) that forms an image on transfer paper, a conveyance path that conveys the transfer paper, and manual feed that feeds the transfer paper to the conveyance path. In an image forming apparatus having a tray 19, a width direction size detection means 30 for detecting the width direction size of transfer paper, and a control means (CPU) 1, the control means 1 is a manual feed tray as a paper feed tray to be used. An image is not formed on the manually fed transfer paper when specified, and the transfer paper size detection mode is detected in which the transfer paper transport direction size is detected by the width direction size detection means. It is one feature.
Further, the width direction size detection means comprising a side guide or the like is provided in the manual feed tray 19, and the control means 1 uses the sensor 30 arranged on the transfer path upstream of the image forming unit on the transfer paper as the conveyance direction size detection means. Another feature is that the transfer paper transport speed during the period from the start of paper feeding from the manual feed tray to the completion of size detection is a slow transport speed applied to thick paper and OHP.

Next, the conveyance path diagram of FIG. 2 will be described. In the operation unit 8, the manual feed tray 19 is designated as the paper feed tray to be used, and the transfer paper size detection mode is selected. The set information is displayed on the display unit 7.
When the transfer paper size detection mode operation is started by an operation from the operation unit 8, paper feeding is started at a slow transport speed applied to thick paper or OHP. As the transfer paper advances along the conveyance path, it reaches the manual paper feed sensor 30. In normal printing, the front end of the transfer paper is abutted against the registration roller 20, the transfer paper is conveyed by a predetermined deflection amount, and then the transfer paper is temporarily stopped.
Then, transfer of the transfer paper is resumed based on a predetermined timing at which the leading edge of the formed transfer image and the leading edge of the transfer paper are synchronized in the secondary transfer unit 21, and when the transfer paper further proceeds in the conveyance path, The leading edge of the transfer paper passes through the fixing roller 23 and the fixing outlet roller 24 and reaches the fixing outlet sensor 26.
The straight paper discharge is a series of transport operations in which the leading edge of the transfer paper passes through the fixing exit sensor 26 and the reversing branch claw 31 also passes through the paper discharge sensor 5 and the paper discharge roller 25 as it is. Pointing. At this time, the transfer paper discharge is completed when the trailing edge of the transfer paper passes the paper discharge sensor 5 as a trigger.
The reverse paper discharge means that the front end of the transfer paper passes through the fixing outlet sensor 26, the transport path is switched downward by the reverse branching claw 31, the front end of the transfer paper passes through the double-side entrance sensor 32, and the rear end of the transfer paper is double-sided. The hitting roller 33 is operated with the passage of the entrance sensor 32 as a trigger, the transfer paper leading edge and the trailing edge are switched, the transfer paper starts reversing with the trailing edge as the leading edge, and the reversing outlet sensor 34 is It refers to a series of operations that pass upward, transport toward the paper discharge port, pass through the paper discharge sensor 5 and paper discharge roller 25, and are discharged out of the apparatus.
Further, the double-sided discharge is the same as the above-described reverse discharge operation until the transfer paper passes through the reverse exit sensor 34, but does not go to the upward discharge path, and the double-side branching claw 36 , And then passes through the double-sided conveyance sensor (left) 37 and further passes through the double-sided conveyance sensor (middle) 38.

The transfer paper further passes through the double-sided conveyance sensor (right) 39, temporarily stops in front of the intermediate roller 17, starts conveyance again from the stopped position, and abuts the transfer paper tip against the registration roller 20. After the transfer paper is conveyed by a predetermined deflection amount, the transfer paper is temporarily stopped.
Then, transfer of the transfer paper is resumed based on a predetermined timing at which the leading edge of the formed transfer image and the leading edge of the transfer paper are synchronized in the secondary transfer unit 21, and when the transfer paper further proceeds in the conveyance path, The leading edge of the transfer paper passes through the fixing roller 23 and the fixing outlet roller 24 and reaches the fixing outlet sensor 26.
After reaching the fixing exit sensor 26, the paper discharge operation is the same as the straight paper discharge. In double-sided paper discharge, the transport operation at the time of size detection in the transfer paper size detection mode is transport to the point where it temporarily stops before the relay roller 17 after passing through the double-sided transport sensor (right) 39 for double-sided paper discharge. .
However, at the time of size detection in the transfer paper size detection mode, abutment on the registration roller 20, image formation of the transfer image, transfer paper temporary stop for synchronization with the transfer image leading edge, and transfer image transfer to the transfer paper The transfer paper is transported while the transfer paper transport speed in a series of operations from the start of paper feeding to the completion of transfer paper size detection is kept constant at a slow speed applied to thick paper and OHP.
Thus, if the time from when the leading edge of the transfer paper reaches the manual paper feed sensor 30 to when the trailing edge of the transfer paper passes through the manual paper feed sensor 30 is measured, the transfer paper is calculated from the conveyance speed and the measured time. Can be calculated.

Note that the width size of the transfer sheet is obtained by the transfer sheet width detecting device 9 incorporated in the manual feed tray 19. For example, the transfer paper width detection device 9 is composed of a side guide or the like incorporated so as to be able to advance and retreat in the width direction of the manual paper feed tray. The transfer paper width detection device 9 contacts the width direction edge of the transfer paper set on the tray. Information on the direction dimension is notified to the control means to determine the width direction dimension. As described above, generally, the width size of the transfer paper is detected from the movement amount of the side guide plate that guides both sides of the transfer paper. In this way, the vertical and horizontal sizes of the transfer paper are determined, and appropriate printing (no transfer image size and transfer paper size mismatch, etc.) can be performed even for irregular-size transfer paper. Further, it is not necessary for the user to measure the size of the irregular transfer paper with a ruler.
Further, by limiting the print mode (paper discharge mode: straight paper discharge, reverse paper discharge, double-side paper discharge) that can be selected by the user in the next printing from the detected vertical size of the transfer paper, Unnecessary jams can be prevented from occurring.
Although detailed description is omitted, FIG. 2 further shows a registration sensor 4, a yellow photosensitive drum 12, a black photosensitive drum 13, a first paper feeding tray 14, a paper feeding sensor 15, a vertical conveyance sensor 16, and a relay roller. 18, a transport belt 22, a second paper feed tray 27, a third paper feed tray 28, and a second paper feed tray 29 are shown.

FIG. 3 is a flowchart for explaining the control of the transfer sheet size detection mode of the image forming apparatus of the present invention. Referring to FIG. 3 together with FIGS. 1 and 2, the transfer sheet size detection mode is set by the operation from the operation unit 8, and the mode is started. First, a paper end check of the manual feed tray 19 is performed (S1).
Here, if the paper end, the paper feeding operation is not performed, and the display unit 7 displays that the transfer paper size detection mode cannot be operated by the paper end. If it is not the paper end, the paper feeding operation is started, and the process proceeds to the transfer paper width size detection process S2 (S2). Based on the information obtained from the transfer paper width detection device 9 incorporated in the manual feed tray 19, the width size of the transfer paper is calculated.
Then, transfer sheet vertical (conveyance direction) size detection processing is performed (S3). First, the sheet feeding operation from the manual feed tray 19 is started. Here, the time from when the leading edge of the transfer paper reaches the manual paper feed sensor 30 to when the trailing edge of the transfer paper passes the manual paper feed sensor 30 is measured, and the vertical size of the transfer paper is determined from the measured time and the conveyance speed. Is calculated.
As described above, in the transfer paper size detection mode, the transfer image is formed, the transfer paper tip is abutted against the registration roller 20 and the transfer paper is temporarily stopped, and the transfer image is transferred to the transfer paper in the secondary transfer unit 21. An operation for transferring a transfer image onto a transfer sheet in a normal printing operation such as transfer of the image is not performed.
When the detection of the vertical size of the transfer paper is completed, a process for determining the detected vertical size is performed (S4). The threshold value that enables all the print modes (straight paper discharge, reverse paper discharge, and double-side paper discharge) that can be used in the manual feed tray 19 recorded in the ROM 3 is compared with the detected vertical size of the transfer paper.
Although straight paper discharge is possible regardless of the vertical size of the transfer paper, it is a printing mode that is always possible, but reverse / double-sided paper discharge is the vertical size of the transfer paper that can be transferred from the layout of the conveyance path of the image forming apparatus. Limited and the minimum and maximum values that can be transported are specified.
As a result of comparing the threshold value with the detected vertical size, it is recorded in the RAM 2 that all print modes can be selected if the threshold value is not exceeded (S5). If it exceeds the threshold value, it is recorded in the RAM 2 that the selectable print mode is only straight paper discharge (S9).
After the step (S9), the sheet is conveyed to the straight paper discharge port and discharged (S10). After the paper discharge is completed and the size-detected transfer paper is in the paper discharge port, the display unit 7 is displayed. (S11).

On the other hand, after step (S5), the conveyance status is determined (S6). Here, it is determined whether or not it is before a point recorded in the ROM 3 where the reversal / double-sided conveyance operation is impossible. If it is before, the process proceeds to step (S7). If not, the process proceeds to step (S10), and thereafter, the process proceeds to step (S11) as described above.
When the process proceeds to step (S7), the transfer paper is conveyed to the double-sided conveyance path, and is stopped before the intermediate roller 17 beyond the double-sided conveyance sensor (right) 39. Thereafter, the process proceeds to step (S7), and the display unit 7 is displayed to notify the user that there is a size-detected transfer sheet on the duplex conveyance path. Thus, the transfer paper size detection mode ends.
In this way, the horizontal and vertical sizes of the transfer paper are clarified, and the print mode that can be selected by the user in printing after the transfer paper size detection mode is either straight discharge or straight / reverse / double-side discharge. It becomes possible to be limited.

It should be noted that the process proceeds to step (S8), and in printing after displaying on the display unit 7 that there is a size-detected transfer sheet on the double-sided conveyance path, the first printing always stops on the double-sided conveyance path. From the transfer paper. The second and subsequent sheets are printed from the manual feed tray 19.
As described above, in the present invention, the double-sided conveyance path is provided, and the control unit 1 performs transfer during the sheet passing before the transfer sheet reaches the position where the conveyance path can be switched to the double-sided conveyance path side in the transfer paper size detection mode. When the paper transport direction size is found, control is performed so that the transfer paper is transported to the duplex transport path.
Further, the control unit 1 controls the transfer paper transported to the double-sided transport path in the transfer paper size detection mode so that the transfer of the transfer paper is stopped on the double-sided transport path when the paper size detection mode ends.
In addition, when the transfer sheet size detection mode is ended in the transfer sheet size detection mode in a state where the transfer sheet is stopped in the double-sided conveyance path, the control unit 1 detects the transfer sheet whose detection has been completed. Control is performed so as to notify the outside that the conveyance path is stopped.
As described above, in the present embodiment, the manual feed tray does not have a mechanical mechanism for detecting the vertical size. Therefore, the manual feed tray can be made compact, and a conventional method for detecting the vertical size has been provided on the conveyance path. By using the manual paper feed sensor existing in the printer, there is no need to add a sensor.
Further, by adopting a slow speed that applies the transport speed during the size detection mode operation to thick paper, OHP, or the like, it is possible to make conditions that make it difficult to damage the transfer paper during transport.
In addition, the horizontal and vertical sizes of the transfer paper are accurately detected by the transfer paper size detection mode, and the cause of the printing error can be reduced by notifying the printing apparatus of the transfer paper size.

1 is a block diagram showing an image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating a conveyance path of the image forming apparatus of the present invention. 6 is a flowchart illustrating control of a transfer sheet size detection mode of the image forming apparatus of the present invention.

Explanation of symbols

1 CPU
9 Width direction size detection means (transfer paper width detection device)
19 Manual tray 30 sensor (conveyance direction size detection means, manual paper feed sensor)

Claims (6)

An image forming unit that forms an image on transfer paper, a transport path that transports the transfer paper, a manual feed tray that feeds the transfer paper to the transport path, and a width-direction size detection unit that detects the width-direction size of the transfer paper And an image forming apparatus having a control unit.
The control means does not form an image on the manually fed transfer paper when a manual feed tray is designated, and detects the transfer paper size in the transfer direction by the width direction size detection means. An image forming apparatus comprising: The width direction size detection means is equipped on the manual feed tray, and the transfer direction size detection means is a sensor disposed on the transfer paper on the upstream side of the image forming unit on the transfer paper,
The control means sets the transfer speed of the transfer paper during a period from the start of feeding from the manual feed tray to the completion of size detection to a constant slow transport speed applied to thick paper and OHP. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1 or 2 further includes a double-sided conveyance path,
In the transfer sheet size detection mode, the control means determines that the double-sided transfer sheet size is determined before the transfer sheet reaches the position where the transfer path can be switched to the double-sided transfer path side. An image forming apparatus, wherein the transfer paper is transported to a transport path.   The control means, in the transfer paper size detection mode, for the transfer paper conveyed to the double-sided conveyance path, stops the transfer paper in the double-sided conveyance path when the paper size detection mode ends. Item 4. The image forming apparatus according to any one of Items 1, 2, or 3.   In the transfer paper size detection mode, when the transfer paper size detection mode is finished in a state where the transfer paper is stopped in the double-sided conveyance path, the control means detects the transfer paper that has finished detecting the transfer paper size. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus notifies the outside that the double-sided conveyance path is stopped.   In the transfer paper size detection mode, the control unit stops the transfer paper on the double-sided conveyance path and ends the transfer paper size detection mode. 5. The selectable print mode is limited when setting for printing after the size detection mode is made according to the detected size in the conveyance direction. The image forming apparatus according to any one of the above.

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