JP2013235039A - Image forming device, method for controlling image forming device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control so that printing is not executed on a surface of a sheet on which the printing is already performed when the printing is performed on the printed sheet.SOLUTION: An image forming device includes: sheet storage means for storing a sheet; conveyance means for conveying the sheet using a double-side conveyance path for printing both sides; and printing means for printing an image on the sheet. A surface of the sheet conveyed using the double-side conveyance path is read, and the printing on the sheet conveyed using the double-side conveyance path is restricted when the read surface is a printed surface. On the other hand, when the read surface is not a printed surface, the printing is performed on the sheet conveyed using the double-side conveyance path.

Description

  The present invention relates to an image forming apparatus that prints an image on a printed sheet, a control method for the image forming apparatus, and a program.

  In the following Patent Document 1, an image reading unit is disposed in a transfer paper transport path from a paper feed unit to a paper discharge unit, so that the document transport system and the transfer paper transport system are used in common.

  In the case of the image forming apparatus as described above, before printing on the document in the paper feed stage by the printing unit, the document in the paper feed stage is read by the reading unit, and the image data of the document is acquired. It is possible to print on the original.

Japanese Patent Laid-Open No. 2000-158881

In recent years, environmental protection and resource saving have been taken up as social problems, and in order to save paper resources, paper on which one side has already been printed (hereinafter referred to as U paper) is an image forming apparatus such as a copier or printer. Increasing use cases. In this case, the user re-accommodates the U paper in the paper feed tray provided in the image forming apparatus and selectively prints on the non-printed side (hereinafter referred to as a non-printed side) ( Reuse of sheets is becoming widespread.
However, since the user does not accurately understand the conveyance path and the paper reversal conveyance process, there is a case where the front and back of the U paper are mistakenly accommodated in the paper feed tray. In such a case, there is a problem that an image is printed on a surface that has already been printed (hereinafter referred to as a printed surface), and an intended printed matter cannot be obtained. In addition, when it is not intended to print an image in an overlapping manner, unnecessary printing may be performed and printing materials and paper may be wasted.
On the other hand, it is not efficient from the viewpoint of cost or the like to provide an image reading unit only for determining whether the surface is not printed or the surface is printed.

  The present invention has been made to solve the above problems, and an object of the present invention is to prevent printing on a printed surface of a printed sheet when printing is performed on the printed sheet. Is to provide a mechanism that can be controlled.

The image forming apparatus of the present invention that achieves the above object has the following configuration.
A sheet storing means for storing the sheet, a conveying means for conveying the sheet using a duplex conveying path for duplex printing, a printing means for printing an image on the sheet, and a printed sheet conveyed from the sheet storing means. A setting unit that sets a print mode for printing an image on a non-printed surface of the sheet, a reading unit that reads the surface of the sheet conveyed using the double-sided conveyance path, and a surface read by the reading unit is printed When the printing mode is set and the surface read by the reading unit is determined to be a printed surface when the printing mode is set, the duplex conveyance path is used. When the printing on the sheet to be conveyed is restricted and the printing mode is set, and it is determined that the surface read by the reading unit is not a printed surface, the double-sided conveyance path is used. Characterized in that it comprises a print control means for controlling the printing of the conveyed sheet, a.
A sheet storage unit for storing the sheet; a printing unit for printing an image on the sheet; and a setting for setting a print mode for printing an image on an unprinted side of a printed sheet conveyed from the sheet storage unit And printing means for the sheet when the printing mode is set and the surface read by the reading means is not a printed surface. And a printing control means for controlling.

  ADVANTAGE OF THE INVENTION According to this invention, when printing on the printed sheet | seat, it can control so that printing is not performed on the surface in which the printed sheet | seat is printed.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an exemplary embodiment. It is a figure which shows the double-sided printing process in the image forming apparatus which shows this embodiment. FIG. 3 is a diagram illustrating a state at the start of reading of a document surface in the image forming apparatus illustrating the embodiment. FIG. 5 is a diagram illustrating a state at the end of reading of a first surface that is a document surface in the image forming apparatus. 6 is a diagram illustrating a state at the start of reading of a second surface, which is the back side of a document in the image forming apparatus. FIG. 6 is a diagram illustrating a state at the end of reading of the back side of the document in the image forming apparatus. FIG. 6 is a diagram illustrating a state where image formation on a recording material in the image forming apparatus is completed. 2 is a block diagram illustrating a control configuration of the image forming apparatus. FIG. FIG. 2 is an explanatory diagram illustrating a configuration of an image reading unit illustrated in FIG. 1. 5 is a flowchart illustrating a method for controlling the image forming apparatus according to the exemplary embodiment. 5 is a flowchart illustrating a method for controlling the image forming apparatus according to the exemplary embodiment. 5 is a flowchart illustrating a method for controlling the image forming apparatus according to the exemplary embodiment.

Next, the best mode for carrying out the present invention will be described with reference to the drawings.
<Description of system configuration>
[First Embodiment]
FIG. 1 is a cross-sectional view illustrating the configuration of the image forming apparatus according to the present exemplary embodiment. Hereinafter, the image forming process will be described. This example shows an example of an image forming apparatus with multiple functions. Note that in the image forming apparatus shown in the present embodiment, a sheet fed from a first sheet feeding unit and a second sheet feeding unit, which will be described later, is called a sheet (sheet), and a sheet that is not used for printing from the second sheet feeding unit To distinguish. However, the second paper feed unit can also feed paper for printing.

  In FIG. 1, a rotatable photosensitive drum 10 serving as an image carrier and a developing roller 11 that rotates in parallel with the photosensitive drum 10 and holds toner are disposed in the center of the image forming apparatus 1. When receiving the print signal, the light emitting unit 21 included in the optical unit 2 irradiates the surface of the rotating photosensitive drum 10 with laser light. The surface of the photosensitive drum 10 irradiated with the laser light forms a latent image with charges. When the toner held is supplied to the latent image on the surface of the photosensitive drum 10 while the developing roller 11 rotates, a toner image is formed on the surface of the photosensitive drum 10.

  On the other hand, the recording material S stored in the first paper feeding unit 30 is conveyed to the conveying roller 40 one by one by the CST pickup roller 31 and the separating unit 32. The conveying roller 40 conveys the recording material S to the transfer unit 15 so that the timing of the toner image on the surface of the photosensitive drum 10 and the leading end position of the recording material S is synchronized. The first sheet feeding unit 30 serving as a sheet storing unit can accommodate a printed sheet that has already been printed on the sheet surface in order to newly feed the sheet. Also, as a printed sheet that can be fed, the first surface to be printed is called a first surface, and the surface that is re-fed and printed in the subsequent reversal process is called a second surface. Needless to say, the first sheet feeding unit 30 can also accommodate sheets whose first and second surfaces are not printed. Furthermore, for the sake of explanation, the conveyance path leading from the first paper supply unit 30 to the double-sided flapper 61 is called a single-sided conveyance path, and is used when a sheet is conveyed when double-sided printing is not performed.

The toner image conveyed to the transfer unit 15 by the rotation of the photosensitive drum 10 is transferred to the recording material S by the applied bias and pressure applied to the transfer unit 15. Further, the transfer unit 15 conveys the recording material S to the fixing unit 50. In the fixing unit 50, the heat from the rotatable heating roller 51 and the pressure of the pressure roller 52 that is opposed to the heating roller 51 and is rotatable fix the toner image on the recording material S. The recording material S on which the toner image is fixed is conveyed to the paper discharge roller 60.
In the case of single-sided printing, the paper discharge roller 60 conveys the recording material S as it is outside the apparatus, and the recording material S is stacked on the first paper discharge unit 70.
Further, the image forming apparatus 1 is controlled by a controller 800 which will be described later with reference to FIG.
FIG. 2 is a diagram showing a double-sided printing process in the image forming apparatus showing the present embodiment. Note that reference numerals not described in FIG. 2 will be described later with reference to FIGS.

In FIG. 2, the double-sided flapper 61 switches the conveyance path after the trailing edge of the recording material S has passed. Thereafter, the paper discharge roller 60 rotates in the reverse direction and conveys the recording material S to the double-sided conveyance path 80. The recording material S that has been switched back is conveyed to the image reading unit 100 via the conveyance roller 41. Thereafter, the recording material S is transported to the transport roller 42 and the transport roller 40, transported again to the transfer unit 15, and stacked on the first paper discharge unit 70 after the toner image is transferred and fixed.
FIG. 3 is a diagram showing a state at the start of reading of the document surface in the image forming apparatus showing the present embodiment. Hereinafter, a process for reading document information and performing double-sided printing on a recording material will be described.

In FIG. 3, the original G stored in the second paper feed unit 90 is conveyed to the conveyance roller 41 one by one by the CIS pickup roller 91 and the separating unit 92. Here, the second paper feeding unit 90 also functions as a document feeding unit, and the image reading unit 100 reads the surface of the document fed from the second paper feeding unit 90 or the surface of the sheet used for printing. It is done. That is, the image reading unit 100 is configured to be able to read both the surface of the sheet fed from the first sheet feeding unit 30 and the surface of the document or sheet fed from the second sheet feeding unit 90. .
On the other hand, the image reading unit 100 emits light to the white reference member 101 and corrects the white reference value before the reading of the first side of the original G, which is the document surface fed from the second paper supply unit 90, starts. carry out. After that, it is driven by the driving means to rotate to a position facing the double-sided conveyance path 80 and stops. The conveyance roller 41 conveys the document G to the image reading unit 100. The image reading unit 100 is already waiting at a position facing the double-sided conveyance path 80, and information read by the image reading unit 100 is stored in the image memory 804, which will be described in detail with reference to FIG. Remembered. Note that the white reference member 101 is disposed downward, and consideration is given to dust adhesion.
FIG. 4 is a diagram illustrating a state at the end of reading of the first surface, which is the document surface, in the image forming apparatus showing the present embodiment.

In FIG. 4, the document G that has passed through the image reading unit 100 is conveyed to the conveyance roller 42. The conveyance roller 42 stops when the trailing edge of the document G passes through the switchback flapper 82. Accordingly, the document G is stopped while being held between the conveyance rollers 42. After the elapse of a predetermined time, the document is conveyed to the original document conveyance path 81.
FIG. 5 is a diagram illustrating a state at the start of reading of the second side, which is the back side of the document, in the image forming apparatus showing the present embodiment.

  In FIG. 5, the switchback flapper 82 switches the conveyance path from the duplex conveyance path 80 to the original document conveyance path 81, and at the same time, the image reading unit 100 rotates to a position facing the original document conveyance path 81 and stops. When the transport roller 42 rotates in the reverse direction, the document G is transported to the image reading unit 100 along the document dedicated transport path 81. The image reading unit 100 is positioned by the CPU 801 controlling the reading position according to the reading mode.

When the original G is conveyed to and passed through the image reading unit 100, information on the second side, which is the back side of the original, is read and stored in the image memory 804 as information on the second side of the original. The recording material S fed from the first paper feeding unit 30 is transported to the transport roller 40 one by one. At substantially the same time, a latent image is formed on the photosensitive drum 10 based on the previous image information from the light emitting unit 21 based on the information on the second side which is the back side of the document stored in the image memory 804. Next, after the toner image formed by the latent image is transferred to the recording material S by the transfer unit 15, the recording material S is conveyed through the fixing unit 50 and the like, and the image formation on the second side of the document is completed.
In FIG. 5, the recording material S is started to be fed at the same time as reading of the information on the second surface, which is the back side of the document, but the recording material S may be conveyed after the information on the second surface is read.
FIG. 6 is a diagram illustrating a state at the end of reading of the back side of the document in the image forming apparatus showing the present embodiment.

In FIG. 6, the document G for which image reading has been completed is transported to the transport roller 43 and the transport roller 44 and stacked on the second paper discharge unit 110. The switchback flapper 82 switches the conveyance path from the document-dedicated conveyance path 81 to the duplex conveyance path 80 so that the recording material S is conveyed in the direction of the conveyance roller 40 when the trailing edge of the document G passes. The recording material S on which the image formation on the second side of the document has been completed conveys the recording material S toward the double-sided conveyance path 80 switched by the double-side flapper 61 by the reverse rotation of the paper discharge roller 60.
FIG. 7 is a diagram illustrating a state in which image formation on the recording material S in the image forming apparatus showing the present embodiment is completed.

  In FIG. 7, the recording material (sheet) S conveyed to the double-sided conveyance path 80 passes through the reversed image reading unit 100, is conveyed to the conveyance roller 40 via the conveyance roller 42, and is further conveyed. As shown in the recording material S indicated by the broken line, the recording material S is conveyed again to the transfer unit 15. The image formation on the second side of the document has already been completed on the recording material S. Therefore, based on the image information on the first surface of the document stored in the image memory 804, the image on the first surface of the document is transferred to the optical unit 2, the photosensitive drum 10, the developing roller 11, the transfer unit 15, and the fixing unit 50. The toner image is transferred and fixed. Thereafter, the sheet is stacked on the first paper discharge unit 70.

  FIG. 8 is a block diagram illustrating a control configuration of the image forming apparatus according to the present exemplary embodiment. Hereinafter, operations of the peripheral unit of the CPU 801 and the operation of the ASIC 802, which are control units of the image forming apparatus 1, will be described. Hereinafter, the configuration of the controller 800 shown in FIG. 1 and the like will be described.

  In FIG. 8, a CPU 801 is connected to a light emitting unit 21 including a polygon mirror, a motor, a laser light emitting element, and the like via an ASIC 802. The CPU 801 controls the optical unit 2 by outputting a control signal to the ASIC 802 in order to draw a desired latent image by scanning the surface of the photosensitive drum 10 with laser light.

  Similarly, the CPU 801 controls a main motor 830 for driving the CST pickup roller 31 and the conveyance roller 40, the photosensitive drum 10, the transfer unit 15, the heating roller 51, and the pressure roller 52 in order to convey the recording material S. . Further, the CPU 801 controls a CST paper feed solenoid 822 that is turned on when the drive of the paper feed roller that feeds the recording material S is started to drive the CST pickup roller 31. Further, the CPU 801 controls a drive system such as a double-sided motor 840 for driving the CIS pickup roller 91 and the conveyance roller 41044.

  Further, the CPU 801 controls the high voltage power source 810 that controls primary charging, development, primary transfer, and secondary transfer bias necessary for the electrophotographic process, as well as the fixing unit 50 and the low voltage power source 811. Further, the CPU 801 monitors the temperature with a thermistor (not shown) provided in the fixing unit 50 and performs control to keep the fixing temperature constant.

  The CPU 801 is connected to the program memory 803 via a bus or the like (not shown). The program memory 803 stores a program and data for executing the above control and all or part of the processing performed by the CPU 801 in each embodiment described in this specification. That is, the CPU 801 executes the operation of each embodiment of the present invention using the program and data stored in the program memory 803.

The ASIC 802 performs motor speed control inside the light emitting unit 21 and speed control of the main motor 830 and the double-sided motor 840 based on an instruction from the CPU 801. The speed control of the motor is performed by detecting a tack signal (pulse signal output from the motor each time the motor is rotated) from the motor (not shown) so that the interval between the tack signals becomes a predetermined time. On the other hand, an acceleration or deceleration signal is output.
As described above, the controller 800 having a circuit based on the hardware of the ASIC 802 has an advantage that the control load on the CPU 801 can be reduced.

  When the CPU 801 receives a print command instructed from a host computer (not shown), the CPU 801 drives the main motor 830, the double-sided motor 840, and the CST paper feed solenoid 822 to convey the recording material S.

After the toner image formed on the surface of the photosensitive drum 10 is transferred by the transfer unit 15 to the recording material S, the toner image is fixed by the fixing unit 50 and then the first recording material stacking unit by the paper discharge roller 60. The paper is discharged to the paper discharge unit 70. In order to improve the alignment of the image-formed recording material, the first paper discharge unit 70 is provided with a gentle upward gradient from the vicinity of the paper discharge port toward the recording material discharge direction. Here, the CPU 801 generates a desired amount of heat by supplying predetermined power to the fixing unit 50 via the low-voltage power supply 811 and applies it to the recording material S, and fuses and fixes the toner image on the recording material. Let
Next, a document reading operation in the image forming apparatus 1 showing the present embodiment will be described.

  When the CPU 801 receives a scan command instructed from a host computer (not shown), it drives the double-sided flapper solenoid 820 and the double-sided motor 840 to operate the CIS paper feed solenoid. Thus, the torque of the double-sided motor 840 is transmitted to the CIS pickup roller 91, and the document G is conveyed. The image reading unit 100 is connected to the ASIC 802 by CISLED, CISSTART, SYSCLK, Sl_in, Sl_select, and Sl_out, which are various control signals described later. The CPU 801 stores an image read from the image reading unit 100 by various controls via the ASIC 802 in an image memory 804 connected to the ASIC 802.

Thereafter, the CPU 801 operates the switchback solenoid 821 to tilt the switchback flapper 82 toward the original document conveying path, reverse the double-sided motor 840, and convey the original G to the second paper discharge unit 110.
Next, a communication operation in the image forming apparatus showing the present embodiment will be described.
The CPU 801 connects to the network 1000 via the network interface 850, and communicates with a host computer (not shown) to input / output image information and device information.
FIG. 9 is an explanatory diagram illustrating the configuration of the image reading unit illustrated in FIG. 1. In the present embodiment, an example of using a CIS sensor (Contact Image Sensor) as an image sensor is shown.

In FIG. 9, reference numeral 901 denotes a contact image sensor (CIS) portion. For example, photodiodes for 10368 pixels are arranged in an array at a specific main scanning density (for example, 1200 dpi). Reference numeral 902 denotes a start pulse CISSTART signal given to the CIS sensor. Reference numeral 915 denotes a transfer clock CISCLK.
914 is a system clock SYSCLK that determines the operating speed of the CIS sensor unit. Reference numeral 908 denotes an A / D converter. Reference numeral 916 denotes a CIS sampling clock ADCLK that determines the sampling speed of the A / D converter. Reference numeral 917 denotes a timing generator. Reference numeral 904 denotes an output buffer. Reference numeral 905 denotes a shift register. Reference numeral 903 denotes a light emitting element control signal (CISLED). Reference numeral 906 denotes current amplification means. A light emitting element 907 irradiates the original G uniformly.
Next, the operation will be described.

  When the CISSTART signal 902 is activated, the CIS sensor unit 901 starts accumulating charges based on the received light, and sequentially sets data in the output buffer 904.

  Next, when a transfer clock CISCLK 915 (for example, about 500 kHz 01 MHz) is given, the data set in the output buffer 904 is transferred to the A / D converter 908 as the CISSNS signal 918 by the shift register 905.

  Since this CISSNS signal 918 has a predetermined data guarantee area, it is necessary to sample after a predetermined time has elapsed from the rising timing of the transfer clock CISCLK 915. The CISSNS signal 918 is output in synchronization with both rising and falling edges of the transfer clock CISCLK 915.

  Therefore, the frequency of the CIS sampling clock ADCLK 916 is generated to be twice that of the transfer clock CISCLK 915, and the CISSNS signal 918 is sampled at the rising edge of the CIS sampling clock ADCLK 916. The timing generator 917 divides the system clock SYSCLK 914 to generate a CIS sampling clock ADCLK 916 and a transfer clock CISCLK 915. The phase of the CIS sampling clock ADCLK 916 is delayed by the data guarantee area compared to the transfer clock CISCLK 915.

The CISSNS signal 918 digitally converted by the A / D converter 908 is controlled at a predetermined timing by the output interface circuit 909 and is output as serial data to the Sl_out signal 910. At this time, the analog output reference voltage is output from the start pulse CISSTART 902 to the CISSNS signal 918 for a predetermined pixel, and cannot be used as an effective pixel.
On the other hand, the A / D conversion gain of the A / D converter 908 can be variably controlled by the control circuit 911 by the Sl_in signal 912 and the Sl_select signal 913.

  For example, when the contrast of the captured image cannot be obtained, the CPU 801 can increase the contrast by increasing the A / D conversion gain of the A / D converter 908 and can always capture with the best contrast.

  Here, a description has been given of a system in which all pixels are output as one CISSNS signal 918. However, for high-speed reading, pixels may be divided into areas and A / D conversion may be performed on a plurality of areas simultaneously. good. Further, although the description has been made so far using the CIS sensor for the image reading unit 100, it is needless to say that the image reading unit 100 can be replaced with a CMOS sensor, a CCD sensor, or the like.

  Next, a description will be given of a process in which a document is read by a document reading unit before printing and it is determined whether the surface is not printed or printed.

FIG. 10 is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. In this example, when the back side printing mode is set, the back side of the sheet fed from the first paper feeding unit 30 is read using the image reading unit 100 before printing, and the non-printed side and printing are performed. It is an example of a printing process in the case of determining which of the surfaces has been completed. In the present embodiment, the back side printing mode refers to a mode for printing on the back side of a sheet that has already been printed on one side of the sheet.
Each step is realized by the CPU 801 of the control unit 5 executing a control program stored in the program memory 803. Hereinafter, in the present embodiment, the printing control and the conveyance control will be described in detail with the control body as the CPU 801.
In step S <b> 1001, the CPU 801 receives a print signal (print instruction) from an information processing apparatus (not illustrated) via the network interface 850.

In step S <b> 1002, the CPU 801 refers to the setting information stored in the program memory 803 and determines whether the setting of the paper feeding unit that feeds the printing paper is the first paper feeding unit 30 or the second paper feeding unit 90. Judging. Note that the paper feed unit is set by an operation unit (not shown) or by a host using the network interface 850.
If the CPU 801 determines that the print sheet is set to be fed from the first sheet feeder 30, the process advances to step S1003. On the other hand, when the CPU 801 determines that the printing paper is fed from the second paper feeding unit 90, the CIS pickup roller 91 and the separating unit 92 are recorded in the second paper feeding unit 90 according to an instruction from the CPU 801. The material S is transported to the transport roller 41, and the process proceeds to S1004.

In step S <b> 1003, according to an instruction from the CPU 801, the recording material S stored in the first paper feeding unit 30 is conveyed to the conveyance roller 40 one by one by the CST pickup roller 31 and the separating unit 32. The conveyance roller 40 conveys the recording material S to the transfer unit 15. In the transfer unit 15, an image is transferred to the conveyed recording material S by driving the transfer roller, and then the recording material S is conveyed to the fixing unit 50. Further, in the fixing unit 50, the recording material S subjected to the heat fixing process is conveyed to the paper discharge roller 60 by driving the fixing roller.
The double-sided flapper 61 switches the conveyance path to the double-sided conveyance path side after the trailing edge of the recording material S passes according to an instruction from the CPU 801. Thereafter, the paper discharge roller 60 rotates in the reverse direction in response to an instruction from the CPU 801 and transports the recording material S to the transport roller 41 through a transport path different from the fixing path. The recording material S is further conveyed to the double-sided conveyance path 80.

In S1004, in response to an instruction from the CPU 801, the image reading unit 100 with the reading surface facing the double-sided conveyance path 80 reads the first surface of the recording material S as described with reference to FIG. At this time, the CPU 801 stores the read image data in the image memory 804.
Next, the recording material S that has passed through the image reading unit 100 is conveyed to the conveying roller 42. The conveyance roller 42 stops when the trailing edge of the recording material S passes through the switchback flapper 82. Therefore, the recording material S stops in a state where it is sandwiched between the conveyance rollers 42.

In step S1005, the CPU 801 analyzes the information (image data) on the first side of the document stored in the image memory 804 in step S1004 and determines whether the printed side (printed side). Perform the process.
Specifically, the CPU 801 binarizes the information on the first side of the document stored in the image memory 804 in S1004. Then, the CPU 801 scans the binarized information on the first side of the document, and determines whether or not a pixel whose pixel value is not “0” is included. If it is determined that a pixel whose pixel value is not “0” is included, it is determined that printing has been completed (printed printing surface). On the other hand, if all the pixel values are “0”, it is determined that the surface is not printed. In addition, a predetermined threshold value may be set as the determination criterion, and control may be performed so as to determine whether the print surface is present.

  In step S <b> 1006, it is determined whether the first side of the read original has been printed. If the CPU 801 determines that the first side has not been printed, it determines that the read side is a printable side. If the CPU 801 determines that the read surface is a “printable surface”, the process advances to step S1007. If the CPU 801 determines that the read surface is not a “printable surface”, the process advances to step S1008.

In step S1007, the CPU 801 conveys the recording material S sandwiched between the conveyance rollers 42 in step S1004 to the conveyance roller 40 to form an image on the reading surface by the conveyance roller 42. The conveying roller 40 conveys the recording material S to the transfer unit 15 so that the toner image on the surface of the photosensitive drum 10 and the timing (registration timing) of the leading end position of the recording material S are matched.
The toner image conveyed to the transfer unit 15 by the rotation of the photosensitive drum 10 is transferred to the recording material S by the applied bias and pressure applied to the transfer unit 15.
Further, the transfer unit 15 conveys the recording material S to the fixing unit 50. In the fixing unit 50, the heat from the rotatable heating roller 51 and the pressure of the pressure roller 52 that is opposed to the heating roller 51 and is rotatable fix the toner image on the recording material S. The recording material S on which the toner image is fixed is conveyed to the paper discharge roller 60. The paper discharge roller 60 conveys the recording material S as it is, and the recording material S is stacked on the first paper discharge unit 70.
At this time, when the double-sided printing process described with reference to FIG. 2 is performed on the recording material S conveyed to the paper discharge roller 60, an image indicating that the back surface is the back surface (the non-printable surface) May be printed. It is assumed that the image indicating the back side is stored in advance in the program memory 803. Further, the position where the image is printed may be controlled so as to be printed at a position where the print surface is hardly affected or a position set by the user. Alternatively, the print report may be controlled to be printed after the last sheet to be printed is discharged.

On the other hand, in S1008, since it may be determined that the read surface is not a printable surface, the recording material S sandwiched between the transport rollers 42 is transported to the transport rollers 40 by the transport rollers 42. The conveyance roller 40 conveys the recording material S to the transfer unit 15. At this time, transfer of the printed image is not executed.
Then, the transfer unit 15 conveys the recording material S to the fixing unit 50. Further, the fixing unit 50 conveys the recording material S to the paper discharge roller 60. The paper discharge roller 60 conveys the recording material S as it is, and the recording material S is stacked on the first paper discharge unit 70. When printing a plurality of pages, a process for determining whether or not the page is the final page is added and S1002 to S1008 may be repeated.

As described above, according to the configuration of the present embodiment, when the back side printing mode is set, even when the user mistakenly accommodates the front and back of the paper in the first paper feeding unit 30, an image can be printed only on the printable side. It becomes possible. In addition, it is possible to print an image indicating that it is the back side of the printed side of the U paper, which is convenient because it is easy for the user to understand which side of the print paper is the front side.
[Second Embodiment]

  In the first embodiment, when a document is read from a printed surface of U paper, the document is discharged as it is, so that printing may not be performed on the printable surface. Further, when the paper is stored in the paper feed tray as U paper but is not actually U paper and both sides are printable sides, an image indicating the back side may be printed on one side. In this embodiment, an image forming apparatus to which the present invention is applied to these problems will be introduced.

  FIG. 11 is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This example is a print processing example in the case of reading a sheet (original) fed using the image reading unit 100 before printing, and determining whether it is an unprinted surface or an already printed surface. . Each step is realized by the CPU 801 of the control unit 5 executing a control program stored in the program memory 803. Further, since S1001 to S1003 in FIG. 11 are the same as S1001 to S1003 in FIG. 10, description of corresponding steps is omitted. The program memory 803 is assumed to be a writable memory. Hereinafter, in the present embodiment, the printing control and the conveyance control will be described in detail with the control body as the CPU 801 of the control unit 5.

In step S1101, according to an instruction from the CPU 801, the image reading unit 100 reads both surfaces of the recording material S according to the process described in the description of FIG. At this time, the CPU 801 refers to the program memory 803 and determines that the reading surface is the first surface when the reading surface information is not held. If the CPU 801 refers to the program memory 803 and determines that the first surface is held in the reading surface information, the CPU 801 determines that the reading surface of the paper that has been fed and read is the second surface. .
Next, the recording material S that has passed through the image reading unit 100 is conveyed to the conveying roller 42. The conveyance roller 42 stops when the trailing edge of the recording material S passes through the switchback flapper 82. Therefore, the recording material S stops in a state where it is sandwiched between the conveyance rollers 42.

  In step S1102, the CPU 801 analyzes the document surface information (image data) stored in the image memory 804 in step S1101 and performs processing for determining whether printing is performed. Specifically, the CPU 801 binarizes the information on the first side of the document stored in the image memory 804 in S1101. The CPU 801 scans the binarized information on the first side of the document, and determines whether or not a pixel whose pixel value is not “0” is included. If it is determined that a pixel whose pixel value is not “0” is included, it is determined that printing has been completed. If it is determined that all the pixel values are “0”, the CPU 801 determines that printing has not been completed.

In step S1103, the CPU 801 determines whether or not both sides of the sheet fed from the first sheet feeding unit 30 have been read. If it is determined that reading has not been completed, the process proceeds to step S1104.
If the CPU 801 determines that both sides of the sheet fed from the first sheet feeding unit 30 have been read, the CPU 801 determines whether the side of the read sheet has been printed. If not, it is determined that the printable surface. Specifically, the CPU 801 scans the binarized information on the first side of the document, and determines that the printing has not been performed when the pixel value is “0”. Further, the CPU 801 records the reading surface information recorded in the program memory 803 and the determination result as to whether it is a printable surface as printable information.
If it is recorded that the reading surface information recorded in the program memory 803 is the second surface, the CPU 801 deletes the reading surface information from the program memory 803 and proceeds to S1105. If it is recorded that the reading surface information recorded in the program memory 803 is the first surface, the CPU 801 advances to S1104.

  In step S <b> 1104, the CPU 801 drives the conveyance roller 42 to convey the recording material S sandwiched between the conveyance rollers 42 to the conveyance roller 40 by the conveyance roller 42. The conveyance roller 40 conveys the recording material S to the transfer unit 15. The transfer unit 15 conveys the recording material S to the fixing unit 50. Further, the fixing unit 50 conveys the recording material S to the paper discharge roller 60. The double-sided flapper 61 switches the conveyance path after the trailing edge of the recording material S has passed. Thereafter, the paper discharge roller 60 rotates in the reverse direction and transports the recording material S to the transport roller 41.

  In step S <b> 1105, the CPU 801 refers to printable information recorded in the program memory 803 and determines whether the second surface is a printable surface. If the CPU 801 determines that the second surface is a printable surface, the process advances to step S1106. If the CPU 801 determines that the second side is not a printable side, the process advances to step S1109.

  In step S <b> 1106, the CPU 801 refers to printable information recorded in the program memory 803 and determines whether the first surface is a printable surface. If the CPU 801 determines that the first surface is a printable surface, the process advances to step S1107. On the other hand, if the CPU 801 determines that the first side is not a printable side, the process advances to step S1108.

In S1107, since both sides of the recording material S can be printed (in the case of a sheet in which both sides are blank), the first printing process is executed. Specifically, the CPU 801 transports the recording material S held by the transport roller 42 to the transport roller 40 by the transport roller 42. The conveying roller 40 conveys the recording material S to the transfer unit 15 so that the timing of the toner image on the surface of the photosensitive drum 10 and the leading end position of the recording material S is synchronized. The toner image conveyed to the transfer unit 15 by the rotation of the photosensitive drum 10 is transferred to the recording material S by the applied bias and pressure applied to the transfer unit 15. Further, the transfer unit 15 conveys the recording material S to the fixing unit 50.
In the fixing unit 50, the heat from the rotatable heating roller 51 and the pressure of the pressure roller 52 that is opposed to the heating roller 51 and is rotatable fix the toner image on the recording material S. The recording material S on which the toner image is fixed is conveyed to the paper discharge roller 60. The paper discharge roller 60 conveys the recording material S as it is, and the recording material S is stacked on the first paper discharge unit 70.
At this time, if the print instruction is double-sided printing, the recording material S conveyed to the paper discharge roller 60 is printed by executing the double-sided printing process described in FIG.

  On the other hand, in S1108, the second printing process is performed when one side of the recording material S is printable and the printing surface for the recording material S is a printable surface. Specifically, the CPU 801 performs the same process as in S1007.

  In step S <b> 1109, the CPU 801 refers to printable information recorded in the program memory 803 and determines whether the first surface is a printable surface. If the CPU 801 determines that the first side is a printable side, the process advances to step S1110. If the CPU 801 determines that the first side is not a printable side, the process advances to step S1112.

In S1110 and S1111, a third printing process is performed when one side of the recording material S is printable and the printing surface for the recording material S is not a printable surface. Specifically, in this process, it is necessary to invert the recording material S so as to be transferred onto the printable surface. Therefore, in S <b> 1110, the CPU 801 transports the recording material S held between the transport rollers 42 to the transport rollers 40 by the transport rollers 42. The conveyance roller 40 conveys the recording material S to the transfer unit 15. In the transfer unit 15, the recording material S is conveyed to the fixing unit 50. Further, the fixing unit 50 conveys the recording material S to the paper discharge roller 60. The double-sided flapper 61 switches the conveyance path after the trailing edge of the recording material S has passed. Thereafter, the paper discharge roller 60 rotates in the reverse direction and transports the recording material S to the transport roller 41.
At this time, an image indicating that the back surface (the surface that is not the printable surface) is the back surface may be printed on the recording material S being conveyed in the manner of the printing process described in FIG.

  In step S1111, the recording material S that has been switched back is conveyed to the image reading unit 100 via the conveyance roller 41. Thereafter, the recording material S is transported to the transport rollers 42 and 40, transported again to the transfer unit 15, and after being transferred and fixed on the toner image, it is stacked on the first paper discharge unit 70, and this processing is completed.

In S1112, processing is performed when both surfaces of the recording material S are not printable surfaces (cannot be printed). Specifically, in S <b> 1112, the recording material S sandwiched between the transport rollers 42 is transported to the transport rollers 40 by the transport rollers 42. The conveyance roller 40 conveys the recording material S to the transfer unit 15. The transfer unit 15 conveys the recording material S to the fixing unit 50. Further, the fixing unit 50 conveys the recording material S to the paper discharge roller 60. The paper discharge roller 60 conveys the recording material S to the outside as it is, and the recording material S is stacked on the first paper discharge unit 70, and this processing is completed.
When printing a plurality of pages, a process for determining whether the processed page is the last page is added, and S1002 to S1112 may be repeated.

According to the present embodiment, even when the user stores the front and back of the U paper in the first paper feeding unit 30 in error, the image can be printed on the intended printing surface. Further, it is possible to print an image indicating that it is the back side of the printed surface of the U paper, and it is easy to understand which side of the printing paper is the front side.
[Third Embodiment]

  In the present exemplary embodiment, an image forming apparatus capable of confirming whether or not to perform a process of printing an image on an intended print surface is assumed on the assumption that U paper is stored in a paper feed tray when a user issues a print instruction. explain.

FIG. 12 is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This example is a print processing example in the case of reading a sheet (original) fed using the image reading unit 100 before printing, and determining whether it is an unprinted surface or an already printed surface. . Each step is realized by the CPU 801 of the control unit 5 executing a control program stored in the program memory 803. Further, since S1001 to S1003 in FIG. 11 are the same as S1001 to S1003 in FIG. 10 and S1101 to S1112 in FIG. The program memory 803 is assumed to be a writable memory. Hereinafter, in the present embodiment, a process for restricting execution of printing based on print control and conveyance control will be described in detail with the control body as the CPU 801. In the present embodiment, a process of determining in S1202 whether or not a designation for performing reading accompanied by generation of printable information is performed.
In step S1201, the CPU 801 receives a print signal as described above. At this time, the print signal is transmitted from the information processing apparatus such as a PC to the image forming apparatus via a print driver by a user operation.

In step S1202, the CPU 801 determines whether to perform printable surface confirmation processing. At this time, information serving as a determination criterion may be stored as setting value information of the image forming apparatus in the program memory 803 of the image forming apparatus.
The user may input an instruction as to whether or not to perform a printable surface confirmation process during a user operation from the information terminal.
In this case, the content of the user instruction is transmitted to the image forming apparatus together with the print signal from the information processing apparatus, and the CPU 801 determines whether or not to perform a printable surface confirmation process from the content of the user instruction. If the CPU 801 determines that the printable surface confirmation process is performed as a result of the determination, the process advances to step S1002. On the other hand, if the CPU 801 determines that the printable surface confirmation process is not performed as a result of the determination, the process advances to step S1203.

  In step S1203, the CPU 801 executes the printing process described in the description of FIG. If the print instruction is double-sided printing, the printing process described in FIG. 1 is executed after the process shown in FIG.

According to the present embodiment, it is possible to instruct whether or not to perform processing for printing an image on an intended printing surface, assuming that U paper is stored in a paper feed tray when a user instructs printing. . As a result, when there is no need to perform a printable surface confirmation process, it is possible to reduce the user's print waiting time from the printing instruction until the printed matter is output.
According to each embodiment, when printing is performed by feeding a printed sheet in the back surface printing mode, if the printed surface of the fed sheet is printed, printing of the fed sheet is performed. It can be controlled not to print on the side.

  Each process of the present invention can also be realized by executing software (program) acquired via a network or various storage media by a processing device (CPU, processor) such as a personal computer (computer).

  The present invention is not limited to the above embodiment, and various modifications (including organic combinations of the embodiments) are possible based on the spirit of the present invention, and these are excluded from the scope of the present invention. is not.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 1st paper feed part 100 Image reading part 801 CPU
802 ASIC
803 Program memory 804 Image memory

Claims (10)

Sheet storage means for storing the sheet;
Conveying means for conveying the sheet using a duplex conveying path for duplex printing;
Printing means for printing an image on a sheet;
Setting means for setting a print mode for printing an image on an unprinted surface of a printed sheet conveyed from the sheet storage means;
Reading means for reading the surface of the sheet conveyed using the double-sided conveyance path;
Determining means for determining whether the surface read by the reading means is a printed surface;
When the printing mode is set, and when it is determined that the surface read by the reading unit is a printed surface, printing on a sheet conveyed using the double-sided conveyance path is limited, and the printing mode is A printing control means for controlling printing on a sheet conveyed using the double-sided conveyance path when it is determined that the surface read by the reading means is not a printed surface;
An image forming apparatus comprising: Sheet storage means for storing the sheet;
Conveying means for conveying the sheet using a duplex conveying path for duplex printing;
Printing means for printing an image on a sheet;
Setting means for setting a print mode for printing an image on an unprinted surface of a printed sheet conveyed from the sheet storage means;
Reading means for reading both sides of the sheet conveyed using the double-sided conveyance path;
Generating means for determining whether each surface read by the reading means is printed or not, and generating printable information;
Holding means for holding printable information for each side of the sheet generated by the generating means;
When the printing mode is set, based on printable information held in the holding unit, a conveyance control unit that controls conveyance of the sheet so that the printing unit prints an image on a non-printed surface;
An image forming apparatus comprising: Determining means for determining whether or not a designation is made to perform reading accompanied by generation of printable information by the generating means;
Both sides of the sheet conveyed by the reading unit using the double-sided conveyance path when the printing mode is set and it is determined that reading with generation of the printable information is performed. The image forming apparatus according to claim 2, wherein:   The image forming apparatus according to claim 1, wherein the sheet storage unit stores a printed sheet on which an image is printed on the first surface or the second surface.   The image forming apparatus according to claim 1, wherein the reading unit reads an image of a conveyed document.   3. The image forming apparatus according to claim 1, wherein the printing unit prints an image on a sheet conveyed from the sheet storage unit based on image data of a document read by the reading unit. Sheet storage means for storing the sheet;
Printing means for printing an image on a sheet;
Setting means for setting a print mode for printing an image on an unprinted surface of a printed sheet conveyed from the sheet storage means;
Reading means for reading the surface of the sheet conveyed from the sheet storage means;
Print control means for controlling printing on the sheet when the printing mode is set and the surface read by the reading means is not a printed surface;
An image forming apparatus comprising: A control method of an image forming apparatus comprising: a sheet storage unit that stores a sheet; a transport unit that transports the sheet using a duplex transport path for duplex printing; and a printing unit that prints an image on a sheet,
A setting step for setting a print mode for printing an image on an unprinted surface of a printed sheet conveyed from the sheet storage unit;
A reading step of reading the surface of the sheet conveyed using the double-sided conveyance path with a reading unit;
A determination step of determining whether the surface read by the reading means is a printed surface;
When the printing mode is set, and when it is determined that the surface read by the reading unit is a printed surface, printing on a sheet conveyed using the double-sided conveyance path is limited, and the printing mode is A printing control step for controlling printing on a sheet conveyed using the double-sided conveyance path when it is determined that the surface read by the reading unit is not a printed surface;
An image forming apparatus control method comprising: A control method for an image forming apparatus, comprising: a sheet storage unit that stores a sheet; and a printing unit that prints an image on the sheet.
A setting step for setting a print mode for printing an image on an unprinted surface of a printed sheet conveyed from the sheet storage unit;
A reading step of reading the surface of the sheet conveyed from the sheet storing means by a reading means;
A printing control step for controlling printing on the sheet when the printing mode is set and the surface read by the reading unit is not a printed surface;
An image forming apparatus control method comprising:   A program for causing a computer to execute the control method for an image forming apparatus according to claim 8.

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