JP2008107654A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure discrimination of wrong paper regardless of a fixing state even when wrong paper is set. <P>SOLUTION: Printing paper is primarily supplied by a paper supplying part 25. A printing part 15 prints an image to printing paper supplied from the paper printing part 25. The fixing part 21 fixes the image formed on the printing paper. A paper length measuring part 49 measures the size of the supplied printing paper. A paper comparing part 49 compares a measured printing paper size and a prescribed paper size which is prescribed and a mismatch between both paper sizes is detected. A control part 45 stops and controls conveying of the printing paper before a fixing part 21 when the mismatch in the size is detected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an improvement of an image forming apparatus suitable for being mounted on, for example, a printer, a copying machine, or a multi-function peripheral (MFP).

  Conventionally, in some types of image forming apparatuses, a printing paper to be printed is set in a paper feeding cassette or the like, and then the paper is designated, and the designated designated paper and the printing paper actually fed are not provided. When the sizes do not match, it often has a function of detecting the mismatch and stopping the operation.

  However, there are cases where it is desired to continue the image forming operation as it is even if the designated paper does not match the supplied printing paper. For example, an image forming apparatus disclosed in Japanese Patent Laid-Open No. 2003-95482 (Patent Document 1) is known. Proposed.

This configuration includes an image forming unit that forms an image based on image information, a paper transport unit that feeds and transports recording paper to the image forming unit, and a paper that detects the size of the fed recording paper. The user sets the size detection means, the detected detection paper size and the specified specified paper size, and the paper size comparison means for detecting the mismatch between the two paper sizes and whether to ignore the paper size mismatch And an image forming unit configured to continue the image forming operation when the setting for ignoring the mismatch is made when the size mismatch is detected and to stop the image forming operation when the setting for ignoring the paper size mismatch is not made. Control means for controlling the image forming operation, and even if the detected paper size and the specified paper size do not match, the user can set whether to continue or stop the image forming operation. It is obtained by.
JP 2003-95482 A

  However, in an image forming apparatus such as that disclosed in Patent Document 1, when the image forming operation is continued, the printing paper passes through the fixing unit once, which may cause a fixing failure on the printing paper. There is a worry that it is misunderstood that it is bad.

  That is, in the image forming apparatus, the image toner transferred and formed on the printing paper is fixed by the heating roller and the pressure roller of the fixing unit, and the fixing temperature of the heating roller is variably controlled according to the size of the printing paper. .

  For this reason, for example, in a simple printer that can specify a different designated paper after setting the print paper in the paper feed cassette, if the printing paper shorter than the designated paper passes through the fixing portion, the temperature of the fixing portion is too high. On the other hand, when a printing sheet longer than the designated sheet passes through the fixing unit, the temperature is too low, and similarly, there is a concern that a fixing defect may occur.

  The present invention has been made to solve such a problem, and even if there is a mistake that the size of the designated paper that is designated for printing differs from the size of the printing paper that is actually set and printed, An object of the present invention is to provide an image forming apparatus capable of reliably determining a sheet error without considering the above.

  In order to solve such a problem, an image forming apparatus according to the present invention includes a paper feeding unit that primarily feeds printing paper, and a printing unit that prints an image on the printing paper fed from the paper feeding unit. A fixing unit for fixing the image printed on the printing paper, a paper length measuring unit for measuring the size of the fed printing paper, and the designated size specified for the printing paper size and the printing paper. A paper comparison unit that compares the paper sizes and detects a mismatch between the two paper sizes, and a control unit that controls the stop of conveyance of the printing paper before the fixing unit when the size mismatch is detected. is doing.

  In the image forming apparatus according to the present invention, the sheet length measuring unit may measure based on detection data from a sensor disposed at a secondary sheet feeding position of the printing sheet fed from the sheet feeding unit.

  In the image forming apparatus of the present invention, a configuration using a registration sensor as the center is also possible.

  The image forming apparatus according to the present invention may have a configuration having a display unit that displays the size mismatch.

  In the image forming apparatus of the present invention, it is also possible to detect the length of the print paper size with respect to the designated paper size in the paper comparison unit and display the length in the display unit.

  In such an image forming apparatus according to the present invention, the printing paper is primarily fed from the paper feeding unit, the image is formed on the printing paper fed from the paper feeding unit by the printing unit, and is formed on the printing paper. The fixed image is fixed by the fixing unit, the size of the fed printing paper is detected by the paper length measurement unit, and the measured paper size is compared with the specified paper size by the paper comparison unit. When the size mismatch is detected, the control unit controls the conveyance of the printing paper to stop before the fixing unit, so even if there is an error in the paper setting, the fixing state is not considered. A mistake can be reliably discriminated.

  In the image forming apparatus of the present invention, in the configuration in which the paper length measuring unit measures based on the detection data from the sensor disposed at the secondary paper feeding position of the printing paper, the printing paper after the secondary paper feeding is conveyed at a stroke. Therefore, the print paper size can be accurately measured.

  In the image forming apparatus according to the present invention, when the sensor is used as a registration sensor, the registration sensor normally provided near the secondary paper feed start position can also be used as a paper measurement unit, which increases the complexity and cost of the configuration. hard.

  In the image forming apparatus according to the present invention, in the configuration having the display unit that displays the size mismatch, it is possible to more reliably determine a sheet error for the fed print sheet through the display.

  In the image forming apparatus of the present invention, in the configuration in which the paper comparison unit detects the length of the print paper size with respect to the designated paper size and the display unit displays the length, the printed paper fed is designated paper It is possible to more reliably discriminate a sheet via a longer or shorter display.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, before describing an embodiment of an image forming apparatus according to the present invention, a schematic mechanism of a printer as an example of an image forming apparatus will be described with reference to FIG.

  In FIG. 1, a semiconductor laser 1 emits a laser beam as a light source toward a rotary polygonal mirror 3, and the laser beam reflected by the rotary polygonal mirror 3 and the mirror 5 is an electrostatic latent image carrier. Scanning is performed on the body drum 7, and an electrostatic latent image is uniformly formed.

  The photosensitive drum 7 is charged by the charging roller 9 before the electrostatic latent image is formed, and the electrostatic latent image is developed with toner from the developing device 11, and the toner image on the photosensitive drum 7 is developed. Is transferred and printed on the printing paper in cooperation with the transfer roller 13.

  That is, the semiconductor laser 1, the rotary polygon mirror 3, the mirror 5, the photosensitive drum 7, the charging roller 9, the developing device 11, the transfer roller 13, and the like form a printing unit 15.

  The printing paper onto which the image has been transferred is fixed (fused) with the transfer toner by a fixing unit 21 including a heating roller 17 and a pressure roller 19 and is discharged from a paper discharge tray (not shown).

  The printing unit 15 and the fixing unit 21 form a main part of the image forming unit 23.

  The printing paper supplied to the photosensitive drum 7 is primarily fed from the paper feeding unit (cassette) 25 by the paper feeding roller 27 through the primary conveying unit 29 and conveyed to the registration roller 31. Reference numeral 33 in FIG. 1 denotes a manual feed tray as a paper feed unit.

  The leading edge of the printing paper conveyed to the registration roller 31 is detected by a registration sensor 35 disposed in front of the registration roller 31 and the length of the printing paper described later is measured. At the timing when the image is stopped and the position is corrected and the image transfer preparation on the photosensitive drum 7 is ready, the paper is secondarily fed by the registration roller 31 to the secondary conveyance unit 37 on the photosensitive drum 7 side. The registration sensor 35 will be further described later.

  FIG. 2 is a block diagram showing an embodiment of the image forming apparatus according to the present invention.

  In FIG. 2, the controller 39 inputs print image data received from an external computer (not shown) via the communication unit 41 and develops it into bit data necessary for printing, and operates the operation display unit 43. The display is controlled and is also connected to the engine control unit 45.

  The operation display unit 43 includes, for example, a liquid crystal display panel disposed in a main body case (not shown) of the image forming apparatus and a liquid crystal operation panel that also serves as a touch switch input unit. In addition to various display input functions such as designation of printing, execution of printing, cancellation, and the like, it has a function of displaying the operation state of the image forming apparatus.

  The engine control unit 45 controls the image forming unit 23, the paper feeding units 25 and 33, the primary and secondary conveyance units (conveyance units) 29 and 37, and forms an image based on a print request from the controller 39. It is a control part which has the function to perform control and others.

  As will be described later, the engine control unit 45 measures the size (paper length) in the conveyance direction of the printing paper that is secondarily fed from the registration roller 31 based on data from the registration sensor 35 of the secondary conveyance unit 37. A sheet length measuring unit 47, and a sheet comparing unit 49 that compares the measurement result (measured value) from the sheet length measuring unit 47 with the dimension in the conveyance direction of the designated sheet and detects a mismatch between the two sheet sizes. When the paper comparison unit 49 detects the size mismatch, the secondary transport unit 37 upstream of the fixing unit 21 is controlled to stop the transport of the second fed paper on the secondary transport unit 37. It has a function to control. Specifically, a transport roller (not shown) that transports printing paper on the secondary transport unit 37 is controlled to stop.

  The dimensions of the designated sheet are based on the designated sheets such as A4, A3, and B4 designated from the operation display unit 43 described above, and for example, a value corresponding to the designated sheet conveyance direction dimension preset in the controller 39 is set to the engine controller 45 Is read.

  When the paper comparison unit 49 detects the size mismatch and the printing paper is longer than the designated paper, the engine control unit 45 displays the display data “printing paper is longer than the designated paper”. If the print paper is shorter than the designated paper, display data indicating that “the print paper is shorter than the designated paper” is formed and output to the operation display unit 43 via the controller 39 for display.

  That is, the paper comparison unit 49 of the engine control unit 45 has a function of detecting the length of the print paper size with respect to the designated paper size, and the operation display unit 43 controls it under the control of the engine control unit 45 and the controller 39. It functions as a display unit for displaying.

  The registration sensor 35 of the transport unit 37 is arranged in front of the registration roller 31 as described above, and detects whether or not the primary fed printing paper has arrived. In addition, it has a function of turning on during printing paper passage and outputting detection data to the paper length measuring unit 47.

  The paper length measuring unit 47 has a function of counting the detection data from the registration sensor 35 with a built-in timer, measuring the paper length of the secondary fed paper, and outputting the measurement result to the paper comparing unit 49. ing.

  Next, the operation of the image forming apparatus of the present invention will be briefly described with reference to the flowchart of FIG.

  When secondary paper feeding is started, the timer of the paper length measuring unit 47 starts in step S1, the detection data from the registration sensor 35 is counted, and the on-time of the registration sensor 35 is designated paper in step S2. Whether the size is longer or shorter than that, that is, whether there is a size mismatch is determined.

  If the ON time of the registration sensor 35 is long or short and step S2 is YES, the printing paper stop process in the secondary conveyance unit 37 is performed in step S3, and the timer of the paper length measurement unit 47 is cleared in step S4. And exit.

  If the on-time of the registration sensor 35 is the same as that of the designated sheet and step S2 is NO, the timer of the sheet length measuring unit 47 is cleared in step S5 and the process ends.

  As described above, in the image forming apparatus according to the present invention, the paper feeding unit 25 that primarily feeds printing paper, the printing unit 15 that prints an image on the printing paper fed from the paper feeding unit 25, and the printing thereof A fixing unit 21 that fixes an image printed on a sheet, a sheet length measuring unit 49 that measures the size of a printing sheet that is disposed at a secondary sheet feeding position and is secondarily fed, and the measured printing sheet size A paper comparison unit 49 that compares the designated paper size and detects a size mismatch, and an engine control unit that controls the stop of the printing paper at the secondary transport unit 37 preceding the fixing unit 21 when the size mismatch is detected ( Controller 45).

  For this reason, since the printing paper is stopped at the secondary conveyance unit 37 before the fixing unit 21, the printing paper is stopped at a position where it can be easily taken out and taken out to the outside in the same manner as when a normal paper jam occurs. In addition, since the printing paper does not pass through the fixing unit 21, the temperature of the fixing unit is not increased too much, and even if there is a mistake in the paper designation, the error of the paper is reliably determined without considering the fixing state. It becomes possible.

  In addition, since measurement is performed using the detection data of the registration sensor 35 arranged at the secondary paper feed position of the fed print paper, the print paper size when the print paper after the secondary paper feed is conveyed all at once. It is measured and the print paper size can be accurately measured.

  Furthermore, since the registration sensor 35 that is normally provided near the secondary paper feed start position is also used as a print paper size detection sensor, it is difficult to increase the complexity and cost of the configuration.

  Furthermore, since the length of the printing paper size detected by the paper comparison unit 49 is displayed on the operation display unit 43, a paper error can be detected more reliably through an indication whether the fed printing paper is longer or shorter than the designated paper. Can be discriminated.

  However, in the image forming apparatus of the present invention, the operation display unit 43 is not limited to the configuration in which the operation display unit 43 displays whether the supplied print sheet is longer or shorter than the designated sheet. The object of the present invention can be achieved without providing the operation display unit 43.

1 is a schematic view showing a copying machine that implements an image forming apparatus according to the present invention. 1 is a block diagram showing an embodiment of an image forming apparatus according to the present invention. 3 is a flowchart for explaining the operation of the image forming apparatus in FIG. 1.

Explanation of symbols

1 Semiconductor laser (printing section)
3 rotating polygon mirror (printing section)
5 Mirror (printing part)
7 Photosensitive drum (printing section)
9 Charging roller (printing section)
11 Developer (printing section)
13 Transfer roller (printing section)
15 Printing section (image forming section)
17 Heating roller (fixing part)
19 Pressure roller (fixing part)
21 Fixing part (image forming part)
23 Image forming unit 25 Paper feeding unit (cassette)
27 Feed roller 29 Primary transport section (transport section)
31 Registration roller 33 Manual feed tray (paper feed unit)
35 Registration sensor (sensor)
37 Secondary transport section (transport section)
39 Controller 41 Communication unit 43 Operation display unit (display unit)
45 Engine control unit 47 Paper length measurement unit 49 Paper comparison unit

Claims (5)

A paper feeding unit that primarily feeds printing paper;
A printing unit for printing an image on the printing paper fed from the paper feeding unit;
A fixing unit for fixing the image printed on the printing paper;
A paper length measuring unit for measuring the size of the fed printing paper,
A paper comparison unit that compares the measured size of the printing paper with the designated paper size designated as the printing paper and detects a mismatch between the two paper sizes;
A control unit that controls to stop the conveyance of the printing paper at a stage preceding the fixing unit when the size mismatch is detected;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the sheet length measurement unit performs measurement based on detection data from a sensor disposed at a secondary sheet feeding position of the printing sheet fed from the sheet feeding unit. The image forming apparatus according to claim 1, wherein the sensor is a registration sensor. The image forming apparatus according to claim 1, further comprising a display unit that displays the size mismatch. The image forming apparatus according to claim 4, wherein the paper comparison unit detects the length of the print paper size with respect to the designated paper size, and the display unit displays the length.

Images