Patent Publication Number: US-9417591-B2

Title: Printing apparatus, method for controlling printing apparatus, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a printing apparatus, a method for controlling the printing apparatus, and a storage medium. 
     2. Description of the Related Art 
     Reverse or two-sided printing of a transparent film sheet, such as an overhead projector (OHP) film, is difficult as it is weak to heat and is high in hardness. The OHP film is assumed to be used for projecting an image via a projector, and thus a desired print seen from the front is acquired even in a case where the image is printed on the back of the sheet. Therefore, according to a technique discussed in Japanese Patent Application Laid-Open No. 2005-216032, in a case where printing is performed on the OHP film, an image to be printed is printed in a normal image or a mirror image according to a print side of a printing apparatus. 
     Specifically, in a case where printing is executed without reversing a fed sheet, in a printing apparatus configured such that the sheet is discharged to a sheet output port with its print side facing down (hereinafter, referred to as longitudinal path engine), an image to be printed is printed in a normal image on the print side in printing on the OHP film. As a result, the sheet is discharged with the print side, on which the normal image has been printed, facing down. In a case where the printing is executed without reversing a fed sheet, in a printing apparatus configured such that the sheet is discharged to a sheet output port with its print side facing up (hereinafter, referred to as straight path engine), an image to be printed is converted into a mirror image and printed on the print side in printing on the OHP film. 
     As a result, the sheet is discharged with the print side, on which the mirror image has been printed, facing up. While the print side of the longitudinal engine and the print side of the straight path engine are different from each other, a print product of which print result is a normal image when the discharged sheet is seen from below can be obtained by both the longitudinal and straight path engines. 
     Since the aforementioned print processing is performed on the OHP film, processing of similar restrictions is performed in a case where the OHP film is used as a cover sheet, a chapter sheet, or an insert sheet. 
     There is a print product using a transparent sheet for a cover sheet, a chapter sheet, or an insert sheet. However, because of the aforementioned print processing, the image can only be printed on the front side. This causes problems where an image cannot be printed on a back side within a single job. Further, even in a case where an image is designated to be printed on a front side, a print product in which an image is printed not in a mirror image but in a normal image on the front side is not always obtained. In order to obtain a desired print product in such a case, a user must understand with which of the longitudinal path engine and the straight path engine a printing apparatus used for printing is provided. Then, when the user understands that he/she cannot obtain a desired result from a currently executing printing job, the user is required to divide the printing job and combine two print products, as illustrated in  FIG. 16 . 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, a printing apparatus includes a determination unit configured to determine, based on a print side designated for a transparent sheet and a print side on which the printing apparatus is able to execute printing, a print side of an image to be printed on the transparent sheet and sheet feeding timing of the transparent sheet, and a printing unit configured to print the image on the transparent sheet based on a content determined by the determination unit. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view illustrating a configuration of a printing apparatus according to an exemplary embodiment. 
         FIG. 2  is a sectional view illustrating a configuration of a printing apparatus according to the present exemplary embodiment. 
         FIG. 3  is a block diagram illustrating a configuration of a printing system to which the printing apparatus is applied. 
         FIG. 4  is a block diagram illustrating a configuration of a software module of the printing apparatus. 
         FIG. 5  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 6  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 7  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 8  is a diagram illustrating a print processing state in the printing apparatus. 
         FIG. 9  is a diagram illustrating a print processing state in the printing apparatus. 
         FIG. 10  is a block diagram illustrating a configuration of a software module of a printing apparatus. 
         FIG. 11  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 12  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 13  is a diagram illustrating a print result on a transparent sheet. 
         FIG. 14  is a flowchart illustrating a method for controlling a printing apparatus. 
         FIG. 15  is a flowchart illustrating a method for controlling the printing apparatus. 
         FIG. 16  is a diagram illustrating a print side on which the printing apparatus executes printing and a print status thereof. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The exemplary embodiments of the present invention will be described with reference to the drawings. 
     &lt;System Configuration&gt; 
       FIG. 1  is a sectional view illustrating a configuration of a printing apparatus according to a first exemplary embodiment. This is an example of the printing apparatus including a path (conveyance path) horizontally extending straight from a manual feed tray to a discharge tray in printing of an image on a transparent sheet. According to the present exemplary embodiment, a multifunction peripheral that includes a scanner unit  2139  and a printer unit  2149  is described as an example of a printing apparatus. 
     In the example illustrated in  FIG. 1 , the scanner unit  2139  feeds a document set on a document feeding device  2250 , and reads an image via an optical system. The document feeding device  2250  is configured to be open/closable and able to read a sheet document or a book document mounted on a platen glass  2211 . A manual feed tray  2151  is used for introducing, to a straight path  2331 , a sheet on which an image is to be formed. An image developed on a photosensitive body  2323  by using a developing unit is transferred onto the sheet by a transfer unit. The image is formed by applying a laser beam emitted from a laser scanner unit  2322  to the surface of the photosensitive body  2323 . A fixing unit  2327  fixes a developer transferred to the sheet by heat pressure. A conveyance path  2335  is used for conveying, to a post-processing unit, the sheet on which the image has been formed. Sheets on which images have been formed are stacked on a discharge tray  2507 . The sheets are housed in feed trays  2311  to  2314 . The sheets fed from the manual feed tray  2151  include plain paper, a transparent sheet (PHP film sheet) and the like. 
     According to the present exemplary embodiment, since the transparent sheet cannot be passed through a curved reversing path, a mirror image is printed from above on the back side of the transparent sheet fed from the manual feed tray  2151 . 
       FIG. 2  is a sectional view illustrating a configuration of a printing apparatus of another type according to the present exemplary embodiment. In printing an image on a transparent sheet, an image formed by each color is transferred to an intermediate transfer body, and the transferred image (normal image) is printed from the left side of the drawing on the front side of the transparent sheet fed along a longitudinal path. 
     A feed tray  2517  houses sheets P as illustrate in  FIG. 2 . A manual feed tray  2520  is configured to feed a transparent sheet not illustrated. In the printing apparatus illustrated in  FIG. 2 , conveyance paths  2518  and  2543  constitute a longitudinal path. 
     A transfer roller  2521  transfers the image of each color transferred to an intermediate transfer belt  2508  in a normal image to the front side of a fed sheet, and a fixing unit  2516  fixes the image by heat pressure. A discharge roller  2512  discharges the printed sheet to a discharge tray  2522  provided outside the machine. 
     An optical unit  2507  emits a laser beam modulated based on print data corresponding to respective colors (yellow (Y), magenta (M), cyan (C), and black (BK)). 
     As described above, the printing apparatus including the straight path can print an image only on the back side of the transparent sheet, while the printing apparatus including the longitudinal path can print an image only on the front side of the sheet. Thus, a user must perform layout or print setting of image data, while being aware which of the straight path and the longitudinal path a printing apparatus to which a job is transmitted is provided with, so that the image can be printed on a correct side of the transparent sheet. Consequently, when erroneous setting is performed, incorrect printing may occur. Hereinafter, printing control performed on the transparent sheet in the printing apparatus according to the present exemplary embodiment will be described in detail. In the printing apparatus adopting an engine configuration illustrated in  FIG. 1 , an engine transfers the image to an image transfer side of a sheet fed from a feed cassette through a conveyance path, namely, a back side, and an upper side of the fed sheet is a front side. This conveyance path is referred to as the straight path. In the printing apparatus adopting an engine configuration illustrated in  FIG. 2 , an engine transfers the image to an image transfer side of a sheet fed from a feed cassette through a conveyance path, namely, a front side, and an upper side of the fed sheet is the front side. In other words, a print side of the fed sheet to which the engine transfers the image and a print side of the sheet are identical to each other. This conveyance path is referred to as a longitudinal path. A specific side of the sheet to which the engine transfers the image is referred to as a second print side, while a side (including front and back sides) of the transparent sheet designated by a job using the transparent sheet described below is referred to as a first print side. 
       FIG. 3  is a block diagram illustrating the configuration of the printing system according to the present exemplary embodiment. 
     The printing apparatus  201  illustrated in  FIG. 3  includes a user interface (UI)  202 , a scanner  203 , feed cassettes  204  and  205 , a discharge tray  206 , an interface (I/F)  207 , and a central processing unit (CPU)  208 . The user interface (UI)  202  includes a touch panel or the like not illustrated, and is configured to display a setting screen necessary in the printing apparatus  201  and receive an instruction from the user. The scanner  203  is configured to read a set document by scanning the set document with an optical unit not illustrated. The feed cassettes  204  and  205  are configured to feed sheets. The I/F  207  is configured to communicate with an information processing apparatus or other printing apparatuses connected to a network  213 . The CPU  208  is configured to control, by using a random access memory (RAM)  209  as a work memory, each unit by executing a control program. 
     A hard disk (HDD)  210  is used as an area for storing a control program necessary for controlling the printing apparatus  201 , a data file, or a user&#39;s job. A printer engine  211  executes printing on the sheets fed from the feed cassettes  204  and  205 , and discharges the printed sheets to the discharge tray  206 . 
       FIG. 4  is a block diagram illustrating a configuration of a software module of the printing apparatus illustrated in  FIG. 3 . The module is operated under control of the CPU  108  in the printing apparatus  201 , and the RAM  209  or the HDD  210  are used as a storage device. 
     A scanner control unit  301  illustrate in  FIG. 4  controls reading of a document set on the scanner  203 . A data analysis unit  302  stores (spools), in the RAM  209  or the HDD  210 , print data  303  generated by analyzing a print job received via the I/F  207 . A print control unit  304  executes processing for feeding sheet from the feed cassettes  204  and  205 , outputting of the print data to the printer engine  211 , and receiving an instruction from the UI  202 . 
       FIG. 5  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. Processing in a copy processing job executed by the scanner control unit  301  up to the point where the print data  303  is obtained from the scanner  203  will be described. Each procedure is achieved through execution of the control program stored in the HDD  210  by the CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 3 . 
     In step S 401 , the processing is started, and the user presses a job start button on the UI  202 . In step S 402 , the scanner control unit  301  analyzes print setting information set by the user using a copy setting screen displayed on the UI  202 , and determines whether there is any setting for using the transparent sheet for a cover sheet, a chapter sheet, or an insert sheet. 
     In a case where the scanner control unit  301  determines that there is no setting for using the transparent sheet for a cover sheet, a chapter sheet, or an insert sheet (NO in step S 402 ), the processing is similar to that of a general case, and thus proceeds to step S 403 . In step S 403 , the scanner control unit  301  determines whether there is any unachievable setting in the print setting information set by the user according to a conventional criterion. In a case where the scanner control unit  301  determines that the print setting information set by the user is achievable (NO in step S 403 ), in step S 404 , the scanner control unit  301  causes the scanner  203  to scan the set document, and stores the print data  303  in the HDD  210 . 
     On the other hand, in a case where the scanner control unit  301  determines that there is unachievable setting in the print setting information set by the user (YES in step S 403 ), the processing proceeds to step S 406 . In step S 406 , a message indicating accordingly is displayed on the UI  202 . Then, in step S 407 , the job processing is interrupted. 
     On the other hand, in a case where the scanner control unit  301  determines that there is setting for using a transparent sheet for a cover sheet, a chapter sheet, or an insert sheet (YES in step S 402 ), in step S 408 , the print control unit  304  determines whether a print side of the transparent sheet is identical to a print side set in the printer engine  211 . In other words, in the case of the printer engine  211  including the longitudinal path illustrated in  FIG. 2 , the print control unit  304  determines whether printing is executed on the print side, of the transparent sheet, which is a side to be discharged to the sheet output port facing down (Face Down). In the case of the printer engine  211  including the straight path illustrated in  FIG. 1 , the print control unit  304  determines whether printing is executed on the print side, of the transparent sheet, which is the side to be discharged to the sheet output port facing up (Face Up). 
     In a case where the scanner control unit  301  determines that the print side (front side) of the transparent sheet is identical to the print side of the printer engine  211  (YES in step S 408 ), printing can be normally executed on the transparent sheet, and general print processing can be performed without performing any special processing according to the present invention. Thus, the processing from step S 403  is executed. 
     On the other hand, in a case where the scanner control unit  301  determines that the print side of the transparent sheet is not identical to the print side of the printer engine  211  (NO in step S 408 ), reversing the transparent sheet is difficult. Therefore, the scanner control unit  301  determines whether a print product can be obtained by reversing sheets other than the transparent sheet. 
     Thus, the scanner control unit  301  determines whether the user has designated Face Up/Down for sheet discharging via the UI  202 . In a case where the scanner control unit  301  determines that the user has designated Face Up/Down for sheet discharging via the UI  202 , in step S 409 , the scanner control unit  301  further determines whether a discharge sheet side of the transparent sheet satisfies the Face Up/Down designation. 
     In a case where the scanner control unit  301  determines that the discharge sheet side of the transparent sheet does not satisfy the Face Up/Down designation (NO in step S 409 ), in step S 406 , a message indicating accordingly is displayed on the UI  202 . Then, in step S 407 , the job is interrupted. 
     As a specific example, a case of the printer engine  211  including the straight path illustrated in FIG.  1  will be described. In a case where printing on the front side of the transparent sheet is designated, and if “Face Up”/“Either is OK” is designated, the user can obtain a desired result. On the other hand, in a case where “Face Down” is designated, the user cannot obtain a desired result. Therefore, the message is output and the job is interrupted. 
     On the other hand, in a case where the scanner control unit  301  determines that the discharge sheet side of the transparent sheet satisfies the Face Up/Down designation (YES in step S 409 ), in step S 410 , the scanner control unit  301  performs an inquiry to the printer engine  211  to determine whether sheets other than the transparent sheet can be reversible. 
     In a case where the scanner control unit  301  determines that there is a sheet not reversible (NO in step S 410 ), in step S 406 , the message indicating accordingly is displayed on the UI  202 . Then, in step S 407 , the job is interrupted. 
     On the other hand, in a case where the scanner control unit  301  determines that the sheets other than the transparent sheet are reversible (YES in step S 410 ), in step S 411 , the scanner control unit  301  further determines whether finishing processing set via the UI  202  by the user can be performed even in a case where the sheet are reversed. 
     As a specific example, in a case where stapling on a right deep side is designated, stapling is required on a left front side if the sheets are reversed. Determination of whether this can be executed is performed. In a case where the scanner control unit  301  determines that the finishing processing cannot be performed (NO in step S 411 ), in step S 406 , a message indicating accordingly is displayed on the UI  202 . Then, in step S 407 , the job is interrupted. 
     In a case where the scanner control unit  301  determines that the finishing processing can be performed (YES in step S 411 ), in step S 404 , the scanner control unit  301  scans the document set on the scanner  203 , and the print data  303  is stored in the HDD  210 . 
       FIG. 6  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. This is a processing example up to the point where the print data  303  is obtained from the network  213 . Each step is achieved through execution of the control program stored in the HDD  210  by the CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 3 . 
     In step S 501 , the processing is started, and printer description language (PDL) data is received via the I/F  207 . In step S 502 , the data analysis unit  302  executes drawing processing to store the print data  303  in the HDD  210 . Then, in step S 503 , the processing is ended. 
     In the case of the PDL data, a printer driver may impose an input limit on a personal computer (PC). However, data can be generated without using any printer driver. Accordingly, since no prior inhibition processing for obtaining data from the scanner  203  as described with reference to  FIG. 6  can be expected, obtaining data is once executed, and setting items are checked in printing. 
       FIG. 7  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. This is a processing example executed by the print control unit  304  to print the print data  303 . 
     In step S 602 , the print control unit  304  analyzes print setting information set in the print data  303 , and determines whether there is any setting using the transparent sheet for a cover sheet, a chapter sheet, or an insert sheet. In a case where the print control unit  304  determines that there is no setting using the transparent sheet for a cover sheet, a chapter sheet, or an insert sheet (NO in step S 602 ), the processing proceeds to step S 603 . In this case, the processing is similar to that of a general case. In step S 603 , the print control unit  304  determines whether there is any unachievable setting in the print setting information set by the user according to a conventional criterion. 
     In a case where the print control unit  304  determines that there is no unachievable setting in the print setting information set by the user according to the conventional criterion (NO in step S 603 ), in other words, the setting is achievable, in step S 604 , the print control unit  304  controls the printer engine  211  to print the print data  303  as instructed. 
     On the other hand, in a case where the print control unit  304  determines that there is an unachievable setting (YES in step S 603 ), in step S 606 , the print control unit  304  further determines whether printing can be executed if the sheet is changed. In a case where the print control unit  304  determines that printing can be executed if the sheet is changed (YES in step S 606 ), in step S 607 , a message indicating absence of an appropriate sheet is displayed on the UI  202 . 
     In a case where the user operates the UI  202  and changes the sheet to a printable sheet (YES in step S 608 ), in step S 604 , the print control unit  304  executes printing by using the changed sheet. 
     On the other hand, in a case where the print control unit  304  determines that sheet changing is not permitted (NO in step S 608 ), and in a case where the print control unit  304  determines that the printing cannot be completed only by changing the sheet (NO in step S 606 ), in step S 609 , the print job is canceled. 
     On the other hand, in a case where the print control unit  304  determines that there is setting using the transparent sheet for a cover sheet, a chapter sheet, or an insert sheet (YES in step S 602 ), in step S 610 , the print control unit  304  determines whether a print side of the transparent sheet is identical to a print side set in the printer engine  211 . 
     In other words, in the case of the longitudinal path engine, the print control unit  304  determines whether printing is executed on the print side, of the transparent sheet, which is the side discharged to the sheet output port facing down. In the case of the straight path engine, the print control unit  304  determines whether printing is executed on the print side, of the transparent sheet, which is the side discharged to the sheet output port facing up. 
     In a case where the print control unit  304  determines that the print side of the transparent sheet is identical to the print side of the engine (YES in step S 610 ), printing can be normally executed on the transparent sheet, and general print processing can be performed without performing any special processing according to the present invention. Thus, the processing from step S 603  is executed. 
     On the other hand, in a case where the print control unit  304  determines that the print side of the transparent sheet is not identical to the print side of the engine (NO in step S 610 ), reversing the transparent sheet is difficult. Thus, the print control unit  304  determines whether a print product can be obtained by reversing sheets other than the transparent sheet. 
     Specifically, the print control unit  304  checks whether the user has designated Face Up/Down of the discharge sheet in the print data  303 . In a case where the print control unit  304  determines that the user has designated Face Up/Down, in step S 611 , the print control unit  304  determines whether the discharge sheet side of the transparent sheet satisfies the Face Up/Down designation. 
     In a case where the print control unit  304  determines that the discharge sheet side of the transparent sheet does not satisfy the Face Up/Down designation (NO in step S 611 ), in step S 609 , the job is canceled. 
     As a specific example, in the printer engine  211  including the straight path illustrated in  FIG. 1 , in a case where printing on the front side of the transparent sheet is designated, and if “Face Up”/“Either is OK” is designated, the user can obtain a desired result. On the other hand, if “Face Down” is designated, the user cannot obtain a desired result. Therefore, the job is canceled. 
     On the other hand, in a case where the print control unit  304  determines that the discharge sheet side of the transparent sheet satisfies the Face Up/Down designation (YES in step S 611 ), in step S 612 , the print control unit  304  performs an inquiry to the printer engine  211  to determine whether sheets other than the transparent sheet are reversible. 
     In a case where the print control unit  304  determines that there is a sheet not reversible (NO in step S 612 ), in step S 609 , the job is canceled. On the other hand, in a case where the print control unit  304  determines that sheets other than the transparent sheet are reversible (YES in step S 612 ), in step S 613 , the print control unit  304  determines whether finishing processing set in the print data  303  can be performed even in a case where the sheets are reversed. 
     As a specific example, in a case where stapling on a right deep side is designated, stapling is required on a left front side if the sheets are reversed. Determination of whether this can be executed is performed. 
     In a case where the print control unit  304  determines that the finishing processing cannot be performed (NO in step S 613 ), in step S 609 , the job is canceled. 
     Further, in a case where the print control unit  304  determines that the finishing processing can be performed (YES in step S 613 ), in step S 614 , the print control unit  304  adjusts a printing order and a print side of the print data  303  to execute printing. 
       FIG. 8  is a diagram illustrating a print processing state in the printing apparatus according to the present exemplary embodiment. This is a printing result example obtained by the longitudinal path engine. 
     In the example illustrated in  FIG. 8 , when data D 1  of print data  101  is designated to be “printed on front side” of a cover sheet of the transparent sheet, and data D 2  and D 3  are designated to be printed on one side of plain paper, a print result  701  is obtained. 
     In the flowchart illustrated in  FIG. 7 , the processing is performed in order of steps S 602 , S 610 , S 603 , and S 604 . First, the transparent sheet is fed and the data D 1  is printed on its front side, and pieces of plain paper are fed to P 2  and P 3  and the data D 2  and D 3  are printed on their front sides. 
     A stacking state  702  illustrates the state where sheets as a print result are stacked on the discharge tray  206 . In the example illustrated in  FIG. 8 , since the printing apparatus illustrated in  FIG. 2  includes the longitudinal path engine, toner is placed on the Face Down side of the transparent sheet with respect to the discharge tray. A stacking state  703  of the print result and sheets illustrates the print result seen from the discharge tray side. 
     On the other hand, the data D 1  of the print data  101  is designated to be “printed on back side” of the cover sheet of the transparent sheet, and the data D 2  and D 3  are designated to be printed on one side of plain paper, a print result  704  is obtained. In the flowchart illustrated in  FIG. 7 , the processing is performed in order of steps S 602 , S 610 , S 611 , S 612 , S 613 , and S 614 . 
     As a result of changing the feeding order and the feed side with the transparent sheet set as a reference in step S 614 , a piece of plain paper is fed to P 1  and the data D 3  is printed on its back side, a piece of plain paper is fed to P 2  and the data D 2  is printed on its back side, and a transparent sheet is fed to P 3  that is a final print page and the data D 1  is printed on its front side. A stacking state  705  illustrates the state of the print result of sheets stacked on the discharge tray. 
     According to the present exemplary embodiment, since the printer engine  211  of the printing apparatus illustrated in  FIG. 2  includes the longitudinal path, the toner is placed on the Face Down side of the transparent sheet with respect to the discharge tray  206 . A stacking state  706  illustrates the print result and stacked sheets seen from the discharge tray side, and a print result  707  is a print result obtained by reversing the print result  706 . When seen from the rear side, it can be understood that printing is performed on the print side desired by the user. 
       FIG. 9  is a diagram illustrating a print processing state in the printing apparatus according to the present exemplary embodiment. This is a printing result example obtained by the printer engine  211  of the printing apparatus illustrated in  FIG. 1  including the straight path. 
     In the example illustrated in  FIG. 9 , when data D 1  of print data  101  is designated to be “printed on front side” of a cover sheet of the transparent sheet, and data D 2  and D 3  are designated to be printed on one side of plain paper, a print result  801  is obtained. In the flowchart illustrated in  FIG. 7 , the processing is performed in order of steps S 602 , S 610 , S 611 , S 612 , S 613 , and S 614 . 
     As a result of changing the feeding order and the feed side with the transparent sheet set as a reference in step S 614 , a piece of plain paper is fed to P 1  and the data D 3  is printed on its back side, a piece of plain paper is fed to P 2  and the data D 2  is printed on its back side, and a transparent sheet is fed to P 3  and the data D 1  is printed on its back side. A stacking state  802  illustrates the print result of sheets stacked on the discharge tray  206 . According to the present exemplary embodiment, since the printer engine  211  including the straight path, toner is placed on the Face Up side of the transparent sheet with respect to the discharge tray  206 . A stacking state  803  is the print result and the sheets seen from the discharge tray side, and a print result  804  is obtained by reversing the print result  803 . When seen from the rear side, it can be understood that printing is carried out on the print side desired by the user. 
     When the data D 1  of the print data  101  is designated to be “printed on back side” of the cover sheet of the transparent sheet, and the data D 2  and D 3  are designated to be printed on one side of plain paper, a print result  805  is obtained. In the flowchart illustrated in  FIG. 7 , the processing is performed in order of steps S 602 , S 610 , S 603 , and S 604 . First, the transparent sheet is fed and the data D 1  is printed on its back side, and pieces of plain paper are fed to P 2  and P 3  and the data D 2  and D 3  are printed on their front sides. 
     A stacking state  806  illustrates the print result of the sheets stacked on the discharge tray. According to the example, since the printer engine  211  including the straight path, toner is placed on the Face UP side of the transparent sheet with respect to the discharge tray  206 . A stacking state  807  illustrates the print result and sheets seen from the side of the discharge tray  206 . 
     According to the present exemplary embodiment, whether the first print side (designated print side (front side or back side) of transparent sheet) and the second print side (specified by configuration of conveyance path included in printer engine  211 ) match each other is determined. In a case where the first print side and the second print side do not match each other, control is carried out as described below. With the first print side set as a reference, the printer engine  211  is controlled so as to perform switching a print side when image data of each page based on print data is printed on the transparent sheet and switching between a normal image and a mirror image of the image data printed on the print side. 
     Thus, the printer engine can be controlled to obtain an intended print result by adapting destination of the print side of the transparent sheet designated by the user. Specifically, the intended print result can be obtained by controlling the printer engine to switch the transparent sheet, the printing order of the pages of the sheets, and a normal image and a mirror image of the image to be formed. 
     According to the first exemplary embodiment, printing on the print side of the transparent sheet is executed as designated by the user. However, since the sheet is a transparent sheet, even in a case where the print side is not the side as desired, a print result may be obtained if an image is printed in a mirror image. 
     In the general case for a cover sheet, a chapter sheet, or an insert sheet, “printing on front side” is only permitted. On the other hand, a second exemplary embodiment provides a user advantage in that “printing on back side” (in appearance of print result) can be performed. Further, as there are more choices of print sides than the first exemplary embodiment, the second exemplary embodiment also provides a user advantage in that a probability of obtaining a print product is higher. Hereinafter, the second exemplary embodiment will be described in detail. 
       FIG. 10  is a block diagram illustrating a configuration of a software module of a printing apparatus according to the present exemplary embodiment. Components similar to those illustrated in  FIG. 4  are denoted by the same reference numerals. 
     The printing apparatus  201  illustrated in  FIG. 10  includes a scanner control unit  901  and a print control unit  902 . 
       FIG. 11  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. This is a processing example executed by the scanner control unit  901  up to the point where print data  303  based on a document image read by a scanner  203  is obtained. Each step is achieved through execution of a control program stored in a HDD  210  by a CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 10 . Steps different from those illustrated in  FIG. 5  will be mainly described. 
     In a case where the scanner control unit  901  determines that the print side of the transparent sheet is not identical to the discharge Face Up/Down designation (NO in step S 409 ), in step S 1001 , the scanner control unit  901  treats an image to be printed on the transparent sheet as an image to be printed in a mirror image. Then, in step S 1002 , the scanner control unit  901  determines a print side of a sheet other than the transparent sheet and whether finishing processing can be performed. 
     On the other hand, in a case where the scanner control unit  901  determines that the setting enables printing (YES in step S 1002 ), in step S 404 , the scanner control unit  901  causes a scanner  203  to start scanning of a set document, and stores the print data  303  in the HDD  210 . 
     On the other hand, in a case where the scanner control unit  901  determines that the setting does not enable printing (NO in step S 1002 ), in step S 406 , a message indicating accordingly is displayed on a UI  202 . In step S 407 , a job is interrupted. Actual mirror-image processing of the print data is executed by the print control unit  902  during printing since the mirror-image processing and printing of PDL data share common processing. 
     In a case where the print control unit  902  determines that sheets other than the transparent sheet cannot be reversible (NO in step S 410 ), from step S 1001 , the print control unit  902  checks whether printing can be completed if the image to be printed on the transparent sheet is treated as the image to be printed in a mirror image. 
     In a case where the print control unit  902  determines that the finishing processing cannot be performed as set due to reversing of the sheet (NO in step S 411 ), from step S 1001 , the print control unit  902  checks whether printing can be completed if the image to be printed on the transparent sheet is treated as the image to be printed in a mirror image. 
       FIG. 12  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. This is a processing example executed by the print control unit  902  for printing print data  303 . Each step is achieved through execution of a control program stored in the HDD  210  by the CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 9 . Steps different from those illustrated in  FIG. 7  will be mainly described. 
     In a case where the print control unit  902  determines that the print side of the transparent sheet does not satisfy the Face Up/Down designation (NO in step S 611 ), in step S 1101 , the print control unit  902  treats an image to be printed on the transparent sheet as an image to be printed in a mirror image. Then, in step S 1102 , the print control unit  902  determines a print side of a sheet other than the transparent sheet and whether finishing processing can be performed. 
     Here, in a case where the print control unit  902  determines that the setting enables printing, in step S 1103 , a mirror image is printed on the transparent sheet. In a case where the print control unit  902  determines that the setting does not enable printing, in step S 609 , the job is canceled. 
     Further, in a case where the print control unit  902  determines that sheets other than the transparent sheet cannot be reversible (NO in step S 612 ), from step S 1101 , the print control unit  902  checks whether printing can be completed if an image to be printed on the transparent sheet is treated as an image to be printed in a mirror image. 
     In a case where the print control unit  902  determines that the finishing processing cannot be performed as set (NO in step S 613 ), from step S 1101 , the print control unit  902  checks whether printing can be completed if an image to be printed on the transparent sheet is treated as an image to be printed in a mirror image. 
       FIG. 13  is a diagram illustrating a print result on the transparent sheet in the printing apparatus according to the present exemplary embodiment. A print result of mirror-image processing executed in a case where a printable side of the transparent sheet and a designated print side are different as described above will be described. 
     In a case where data D 1  of print data  101  is designated to be “printed on back side” of a cover sheet of the transparent sheet in the longitudinal path engine, data D 2  and D 3  are printed on one side of plain paper, and the data D 1  is determined to be printed in a mirror image, a print result  1201  is obtained. A stacking state  1202  is the print result of sheets stacked on the discharge tray. Since the printer engine  211  according to this example includes the longitudinal path, toner is placed on the Face Down side of the transparent sheet with respect to the discharge tray  206 . A stacking state  1203  illustrates the print result and sheets seen from the discharge tray side. 
     On the other hand, in the printer engine  211  of the printing apparatus illustrated in  FIG. 1  including the straight path, the data D 1  of the print data  101  is designated to be “printed on front side” of the cover sheet of the transparent sheet. In a case where the data D 2  and D 3  are printed on one side of plain paper, and the data D 1  is determined to be printed in a mirror image, a print result  1204  is obtained. A stacking state  1205  is the print result of sheets stacked on the discharge tray. According to the present exemplary embodiment, since the printer engine  211  includes the straight path, toner is placed on the Face Up side of the transparent sheet with respect to the discharge tray  206 . A stacking state  1206  illustrates the print result and sheets seen from the discharge tray side. 
     According to the second exemplary embodiment, the mirror image printing is automatically performed in a case where the processing cannot be carried out as instructed by the user. Alternatively, similar processing can be obtained even in a case where the user selects permission/inhibition of the mirror image printing. 
       FIG. 14  is a flowchart illustrating a method for controlling a printing apparatus according to a third exemplary embodiment. Each step is achieved through execution of a control program stored in a HDD  210  by a CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 10 . Steps different from those illustrated in  FIGS. 5 and 7  will be mainly described. 
     Before step S 1001 , in step S 1301 , a scanner control unit  901  determines whether mirror image printing is permitted. In a case where the scanner control unit  901  determines that a user permits mirror image printing (YES in step S 1301 ), the processing from step S 1001  is executed. In a case where the scanner control unit  901  determines that the user does not permit mirror image printing (NO in step S 1301 ), the processing from step S 406  is executed. 
       FIG. 15  is a flowchart illustrating a method for controlling the printing apparatus according to the present exemplary embodiment. This is a print processing example of print data  303  executed by a print control unit  902  in a case where the print control unit  902  includes determination processing for “permission/inhibition” of the mirror image printing. Each step is achieved through execution of a control program stored in the HDD  210  by the CPU  208 . Hereinafter, processing will be appropriately described mainly on the module illustrated in  FIG. 10 . Steps different from those illustrated in  FIGS. 5 and 7  will be mainly described. 
     Before step S 1101 , in step S 1301 , the print control unit  902  determines whether mirror image printing is permitted. In a case where the print control unit  902  determines that the user permits mirror image printing (YES in step S 1301 ), the processing from step S 1101  is executed. In a case where the print control unit  902  determines that the user does not permit mirror image printing (NO in step S 1301 ), the processing from step S 609  is executed. 
     According to the second exemplary embodiment, the mirror image printing is automatically performed in a case where the processing cannot be carried out as instructed by the user. Alternatively, similar processing can be obtained even in a case where a printing machine retains information, for example, according to a market where a printing apparatus is provided for, in other words, in a printing machine of a Point of Distribution (POD) system where the user wishes to control all, mirror image printing is not permitted, in other words, in a printing machine of an office system where much time and labor are avoided, mirror image printing is permitted. 
     According to each of the exemplary embodiments, in a case where a sheet, such as a transparent sheet on which reverse or two-sided printing is difficult is used for a cover sheet, a chapter sheet, or an insert sheet, “printing on front side” and “printing on back side” are enabled. Further, a desired print result can be obtained by a single job while a demand that priority be placed on a side to be printed or a print result be good enough as long as it is correct in appearance is accommodated. 
     Each process of the present invention can also be achieved through execution of software (program) acquired via a network or various types of storage media by a processing apparatus (CPU or processor) such as a PC (computer). 
     Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2014-068258 filed Mar. 28, 2014, which is hereby incorporated by reference herein in its entirety.