Image forming apparatus which detects a blank page from an image of a document, method for controlling the same, and storage medium

In a case where a conveyed document is a first page, printing is started before a result of determination as to whether the document is a blank page is output, whereby a time until a first sheet is output can be shortened.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an image forming apparatus, a method for controlling the image forming apparatus, and a storage medium.

Description of the Related Art

In image forming apparatuses such as a digital copying machine, there are mainly two types of document reading methods. One is a method (an optical system moving method) of placing a document on a platen to fix a document position and reading an image by reciprocating an optical system to scan the document. The other is a method (a feeding-reading method) of fixing the position of an optical system and reading an image while conveying a document by a document feeding unit (a document feeder (DF)).

Conventionally, in the image forming apparatuses such as the digital copying machine, even a blank page having no image printed thereon has been subjected to print processing when a read document is output, causing unnecessary paper consumption. Thus, there has been developed a blank page detection technology for suppressing unnecessary paper consumption by removing pages determined to be blank (Japanese Patent Application Laid-Open No. 2010-178377).

In the conventional technology, irrespective of what number-th page the read document is, printing has been started after output of a result of determination as to whether the read document is blank.

When a surface of a document placed on the DF is blank, a user is likely to recognize that the document is blank.

However, in the conventional technology, even for the first page, printing has been started after output of blank determination result, and thus the printing start has been delayed.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an image forming apparatus includes a reading unit configured to read an image of a conveyed document, a printing unit configured to print, on a sheet, the image of the document read by the reading unit, a detection unit configured to detect a blank page from the image of the document read by the reading unit, a determination unit configured to determine whether the document read by the reading unit is a first page, and a control unit configured to, in a case where the determination unit determines that the document read by the reading unit is a first page, notify the printing unit of completion of image output preparation before the detection unit detects a blank page, and in a case where the determination unit determines that the document read by the reading unit is not a first page, notify the printing unit of the completion of the image output preparation after the detection unit detects the blank page.

DESCRIPTION OF THE EMBODIMENTS

<Description of System Configuration>

[Outline of Image Forming Apparatus400]

FIG. 1is a diagram illustrating a configuration of an image forming system including an image forming apparatus according to a first exemplary embodiment.

InFIG. 1, an image forming apparatus400is connected to a host computer via a local area network (LAN)600such as Ethernet (registered trademark). The present exemplary embodiment is directed to a case where two computers, specifically, first and second host computers (hereinafter, simply referred to as host computers)610and620, are connected to the image forming apparatus400.

The image forming apparatus400includes a reader device (scanner unit)200configured to read image data, and a printer device (printer unit)300configured to output the image data. The image forming apparatus400also includes an operation unit150including a keyboard for inputting/outputting the image data and a liquid crystal panel for displaying/setting the image data or various types of functions.

The image forming apparatus400further includes a storage unit114configured to store image data read by controlling the scanner unit200and image data generated from code data received from the host computers610and620via the LAN600. A control device (controller unit)100including a single electronic component and configured to control these components is connected.

The scanner unit200includes a document feeding unit280configured to convey a document sheet, and a scanner unit210configured to optically read a document image and convert the read image into image data as an electric signal. The printer unit300includes a printer unit310including, for example, a sheet feeding cassette configured to store a sheet on which printing is to be performed, and a unit configured to transfer/fix the image data onto a print sheet. The printer unit300also includes a finishing unit500configured to execute sort processing or staple processing on a recording sheet on which printing has been performed.

The controller unit100includes a plurality of functional blocks: for example, a copy function of reading the image data of the document by controlling the scanner unit200and outputting the image data on the recording sheet by controlling the printer unit300, a scanner function of converting the image data read from the scanner unit200into code data and transmitting the code data to the host computers610and620via the LAN600, and a printer function of converting the code data received from the host computers via the LAN600into image data and outputting the image data to the printer unit300.

FIG. 2is a block diagram illustrating a configuration of the image forming apparatus400illustrated inFIG. 1. Hereinafter, the controller unit100of the image forming apparatus400will be described in detail.

InFIG. 2, the controller unit100is connected to the scanner unit200serving as an image input device, and controls input of image information. Meanwhile, the controller unit100is connected to the LAN600, and transmits a transmission job via the LAN600. The controller unit100is further connected to the printer unit300serving as an image output device, and controls output of the image information. A central processing unit (CPU)111controls an operation of the image forming apparatus400, and operates based on a program stored in a random access memory (RAM)112. A read-only memory (ROM)113is a boot ROM configured to store a boot program of a system.

The storage unit114stores, for example, system software, image data, and a program for controlling the operation of the image forming apparatus400. The programs stored in the ROM113and the storage unit114are loaded into the RAM112, and the CPU111controls, based on the programs, the operation of the image forming apparatus400. An image processing unit115executes image correction on image data input from a scanner interface (I/F)117.

A network I/F116is connected to the LAN600, and inputs or outputs various types of information via the network. The scanner I/F117connects the scanner unit200serving as an image input device and the controller unit100to execute synchronous or asynchronous conversion of the image data. An operation unit I/F118is an interface for connecting the operation unit150and the controller unit100, and outputs, to the operation unit150, the image data to be displayed thereon.

In addition, the operation unit I/F118transmits, to the CPU111, information input by a user from the operation unit150. A printer I/F119connects the printer unit300serving as an image output device and the controller unit100to execute synchronous or asynchronous conversion of the image data, and image processing for print output. The operation unit150includes an input device for enabling the user to issue an execution instruction of a function of the image forming apparatus400, or to perform an operation setting for the execution of the function. The operation unit150also includes a display device for notifying the user of a state of the image forming apparatus400.

[Configuration of Image Forming Apparatus400]

FIG. 3is a sectional view illustrating an example of the image forming apparatus400illustrated inFIG. 1.

First, the scanner unit200will be described. Detailed description will be given below.

In the scanner unit200, the document feeding unit (DF unit)280feeds documents one by one starting from the first page, to a platen glass1401, and discharges the documents on the platen glass1401after the end of a document reading operation.

The documents conveyed onto the platen glass1401are illuminated by an illumination lamp1402in a first mirror unit1409. Reflected light generated by the illumination passes through mirrors1403,1404, and1405, and forms, by a lens1406, an image on a charge-coupled device (CCD) sensor (hereinafter, referred to as CCD)1407. Accordingly, a scanned document image is read by the CCD1407. Image data output from the CCD1407is subjected to predetermined processing to be transferred to the controller unit100.

Next, the printer unit300will be described.

The printer unit300includes a laser driver321configured to drive a laser emission unit322. The laser driver321causes the laser emission unit322to emit a laser beam according to the image data output from the controller unit100. This laser beam is applied onto a photosensitive drum323, and a latent image according to the laser beam is formed on the photosensitive drum323. A developer is adhered by a developing device324to the latent image part of the photosensitive drum323.

The printer unit300includes cassettes311,312,313, and314, each of which functions as a sheet feeding unit and has a drawer shape. The user draws each sheet feeding cassette, supplies sheets into the drawn cassette, and then closes the cassette.

The printer unit300feeds a recording sheet from any of the cassettes311to314, and conveys the recording sheet through a conveyance path331to a transfer unit325. The transfer unit325transfers the developer adhered to the photosensitive drum323onto the recording sheet. The recording sheet carrying the developer is conveyed to a fixing unit327by a conveyance belt326, and the developer is fixed onto the recording sheet by heat and pressure of the fixing unit327.

Then, the recording sheet having passed through the fixing unit327passes through conveyance paths335and334to be discharged. For discharging the recording sheet by reversing a print side, the recording sheet is led to conveyance paths336and338, and conveyed in a reverse direction to be passed through conveyance paths337and334. When two-sided recording is set, after passing through the fixing unit327, the recording sheet is led from the conveyance path336to a conveyance path333by a flapper329, and then conveyed in a reverse direction to be led to the conveyance path338and a sheet refeeding conveyance path332by the flapper329. The recording sheet led to the sheet refeeding conveyance path332passes through the conveyance path331at the aforementioned timing to be led to the transfer unit325. Irrespective of one-sided or two-sided recording, the recording sheet discharged from the conveyance path334is conveyed to the finishing unit500.

The recording sheet conveyed to the finishing unit500is initially fed to a buffer unit501. Depending on cases, the conveyed recording sheet is wound around a buffer roller to be buffered. For example, when processing such as stapling to be performed on the downstream side takes time, the use of the buffer unit501enables a conveyance speed of the recording sheet conveyed from the main apparatus to be maintained constant, thereby contributing to improvement of throughput.

Then, the recording sheet is passed through a conveyance path510by an upstream discharge roller pair502and a downstream discharge roller pair503to be discharged to a discharge tray507.

In the case of a staple mode, the recording sheet conveyed by the upstream discharge roller pair502is pulled back by a knurling belt504immediately after a rear end of the recording sheet passes through the roller pair502, and discharged to a stack tray505. Then, after a predetermined number of recording sheets are stacked, the recording sheets are subjected to staple processing by a stapling unit506, and discharged to the discharge tray507by the downstream discharge roller pair503.

In the case of shift sorting, sheets stacked on the stack tray are shifted left and right, and discharged to the discharge tray507, thereby representing separation between sets of documents. In the case of normal stapling, after the recording sheets discharged from the conveyance path334are stacked on the stack tray505, stapling is performed.

FIG. 4is a sectional view illustrating a configuration of the scanner unit200illustrated inFIG. 3.

Referring toFIG. 4, main components and a reading operation of the scanner unit200using a linear image sensor, according to the present exemplary embodiment will be described.FIG. 4schematically illustrates main components and a reading operation particularly in the case of “feeding-reading”, that is, reading the document by operating the document feeding unit280.

InFIG. 4, a document bundle100P to be read is placed on a tray142. A feeding roller1411, a separation conveyance roller1412, and a registration roller1413are arranged in a lower part of a document conveyance direction. The feeding roller1411is rotated by a driving source (not illustrated) to feed the document bundle100P placed on the tray142. Then, the separation conveyance roller1412disposed downstream of the feeding roller1411separates an uppermost document from the conveyed document bundle100P to convey the document. A rotational start of the registration roller1413disposed on the downstream side of the separation conveyance roller1412is used as a reference of a conveyance timing of the document and an image reading timing thereafter.

A driving source for driving the feeding roller1411, the separation conveyance roller1412, and the registration roller1413is, for example, a stepping motor.

The document discharged from the registration roller1413advances along a guide plate1418, is nipped between a rotating large-diameter conveyance drum1415and driven rollers1416a,1416b, and1416c, and is conveyed along an outer circumference of the conveyance drum1415. At this time, the document is conveyed through a surface of the platen glass1401of the scanner unit210in a direction indicated by an arrow illustrated inFIG. 4, and image reading is carried out. After the image reading, the document is conveyed along the outer circumference of the conveyance drum1415, and discharged by a discharge roller1417.

In the feeding-reading mode, since the documents only need to be conveyed in a fixed direction, a large volume of documents can be continuously read at a high speed.

In the feeding-reading mode, the document passes through the surface of the platen glass1401of the scanner unit210. At this time, the first mirror unit1409and a second mirror unit1410are moved by a motor1408to be fixed at positions illustrated in the drawing. The document is illuminated by the illumination lamp1402in the first mirror unit1409when it faces the surface of the platen glass1401. Reflected light generated by the illumination passes through the mirrors1403to1405, and forms, by the lens1406, an image on the CCD sensor1407serving as a reading device220(FIG. 5).

FIG. 5is a diagram illustrating an internal configuration of the scanner unit210illustrated inFIG. 4. Hereinafter, document reading performed in the scanner unit210will be described.

InFIG. 5, the reading device220includes a line sensor such as a CCD sensor, a complementary metal-oxide semiconductor (CMOS) sensor, or a contact image sensor (CIS). The image data of the document is read via the CCD sensor1407serving as the reading unit220, and the read analog image data is output to a subsequent stage processing unit. An analog-to-digital (A/D) conversion unit230converts the data read by the reading device220into digital data.

A read image processing unit240executes processing such as shading correction for matching, in level, a highlight part (white) of the read image data with a dark part (black) thereof, modulation transfer function (MTF) correction, or high frequency suppression processing. A blank page detection processing unit250refers to image data301processed by the read image processing unit240to detect whether the read image data is a blank page. The scanner unit210outputs the image data301, which has been obtained by performing image processing on the read document image data by the read image processing unit240, together with a blank page detection result302by the blank page detection processing unit250.

The output data and the blank page detection result of the scanner unit210are transferred to the storage unit114based on control of the controller unit100. The storage unit114stores the transferred image data and the blank page detection result (a blank page flag).

[Blank Page Detection Processing Unit250]

FIG. 6is a diagram illustrating an internal configuration of the blank page detection processing unit250illustrated inFIG. 5.

InFIG. 6, the blank page detection processing unit250is connected to a register (not illustrated), and a control parameter and a processing result are stored therein. Writing in the register is carried out by the CPU111and the blank page detection processing unit250, and the blank page detection processing unit250reads the control parameter set in the register to operate.

The image data301is digital image data output from the read image processing unit240. The output result302from the blank page detection processing unit250is a signal indicating whether the digital image data is a blank page. An area control unit303controls an area for generating a histogram or edge information from the input image data.

A histogram generation unit304generates a histogram of a plurality of areas by using the image data301. A histogram analysis unit305determines whether the document image is a blank page, based on the histogram generated by the histogram generation unit304. An edge information generation unit306counts edges of a plurality of areas by using the image data301.

An edge information analysis unit307determines whether the document image is a blank page, based on the number of edges generated by the edge information generation unit306. A blank page determination unit308refers to a result of a plurality of threshold parameters used by the histogram analysis unit305and the edge information analysis unit307to output a result of determination as to whether the document is a blank page.

[Schematic Diagram of Image Data and Blank Page Flag]

FIG. 7is a diagram illustrating an image file or a document file stored in a document storage area constituting a part of the storage unit114illustrated inFIG. 2.

In an example illustrated inFIG. 7, two document files of documents1and2are illustrated. The document1includes document information and three pages of pages1to3. Each page stores a “blank page flag” determined by the blank page detection processing unit250and “image data” output from the read image processing unit240as a set. Similarly, the document2includes document information and two pages of pages1and2. Each page includes a set of a blank page flag and image data to be stored. In this example, pages where blank page flags are ON, that is, image data of “the page2of the document1” and “the page2of the document2”, are blank page image data.

FIG. 8is a diagram illustrating a configuration example of the operation unit150illustrated inFIG. 2.

InFIG. 8, a liquid crystal operation panel151, which is formed by combining a liquid crystal with a touch panel, displays an operation screen, and when a display key is pressed by the user, transmits the information to the controller unit100. Main mode setting and status display are carried out thereon. A start key152is used when a reading and printing operation of the document image is started or when a start of other functions is instructed. The start key152includes two-color LEDs of green and red. Lighting of the green LED indicates that an operation can be started. Lighting of the red LED indicates that an operation cannot be started. A stop key153has a function of stopping the on-going operation. A hard key group154includes a numerical keypad, a clear key, a reset key, a guide key, and a user mode key.

FIG. 9is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This is an example of copy processing executed when a document is placed on the document feeding unit (DF unit)280. A program related to the processing in the flowchart is controlled by the CPU111of the controller unit100sequentially loading the programs stored in the ROM113and the storage unit114into the RAM112to execute the programs.

Setting is carried out on a mode setting screen of the copy function via the liquid crystal operation panel151illustrated inFIG. 8. When the start key152is pressed, the processing is started. Since each setting mode of the copy function has a default value, the copy processing is started even when the start key152is pressed without performing setting. Each setting value is stored in the RAM112so as to be referred to in each process.

In step S901, the CPU111determines whether an operation mode is a first copy output time (FCOT) mode when copying from the document feeding unit (DF unit)280. The CPU111stores a determination result of the FCOT mode in the RAM112. In step S902, the CPU111activates scan processing. In step S903, the CPU111waits for notification of completion of output preparation from the scan processing. When the CPU111detects the completion of the output preparation from the scan processing (YES in step S903), the processing proceeds to step S904. In step S904, the CPU111activates print processing to end this processing.

FIG. 10is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This is an example of processing of determining whether an operation is performed with priority given to the FCOT mode (hereinafter, referred to as a DF FCOT mode) in the copy processing executed when the document is placed on the document feeding unit (DF unit)280, based on set image forming conditions. A program related to the processing in the flowchart is controlled by the CPU111of the controller unit100sequentially loading the programs stored in the ROM113and the storage unit114into the RAM112to execute the programs. In the present exemplary embodiment, the image forming conditions include a document conveyance state, an image processing state of an image to be read from the document, and a document size. The image forming conditions further include a feeding destination definition state of a sheet to be fed by the printer device300, a designation state of a print side of the sheet on which printing is to be performed, and a post-processing setting state of the sheet on which printing has been performed.

In step S1001, the CPU111determines whether an operation is document reading from the document feeding unit (DF unit)280. When the CPU111determines that the operation is document reading from the DF unit280(YES in step S1001), the processing proceeds to step S1002. When the CPU111determines that the operation is not document reading from the DF unit280(NO in step S1001), the processing proceeds to step S1010.

In step S1002, the CPU111determines whether a document size has been defined. The case where the document size has been defined refers to a case where the document size has been identified by, for example, user's designation of the document size via the operation unit150or detection of the document size by a sensor of the document feeding unit280. When the CPU111determines that a document size has been defined (YES in step S1002), the processing proceeds to step S1003. When the CPU111determines that a document size has not been defined (NO in step S1002), the processing proceeds to step S1010.

In step S1003, the CPU111determines whether a recording sheet feeding source has been defined, based on the document size defined in step S1002. When the CPU111determines that a recording sheet feeding source has been defined (YES in step S1003), the processing proceeds to step S1004. When the CPU111determines that a recording sheet feeding source has not been defined (NO in step S1003), the processing proceeds to step S1010.

In step S1004, the CPU111determines whether a print color mode such as a monochrome, color, auto, or single color mode has been defined. When the CPU111determines that a color mode has been defined (YES in step S1004), the processing proceeds to step S1005. When the CPU111determines that a color mode has not been defined (NO in step S1004), the processing proceeds to step S1010.

In step S1005, the CPU111determines whether a mode requiring image processing has not been set. In the present exemplary embodiment, the mode requiring image processing is, for example, repeated output, reduced/enlarged layout, enlarged continuous shooting, area processing, a scaling rate, image shifting, numbering, a stamp, a document number printing, bookbinding, image combining, a background pattern, or security information embedding.

When the CPU111determines that a mode requiring image processing has not been set (NO in step S1005), the processing proceeds to step S1006. When the CPU111determines that a mode requiring image processing has been set (YES in step S1005), the processing proceeds to step S1010.

In step S1006, the CPU111determines whether an operation is one-sided printing. When the CPU111determines that the operation is one-sided printing (YES in step S1006), the processing proceeds to step S1007. When the CPU111determines that the operation is not one-sided printing (NO in step S1006), the processing proceeds to step S1010.

In step S1007, the CPU111determines whether finishing processing such as stapling, punching, or folding has not been set. When the CPU111determines that finishing processing has not been set (NO in step S1007), the processing proceeds to step S1008. When the CPU111determines that finishing processing has been set (YES in step S1007), the processing proceeds to step S1010.

In step S1008, the CPU111determines whether a continuous reading mode for repeatedly reading documents from the document feeding unit280or a pressing plate before print output has not been set. When the CPU111determines that a continuous reading mode has not been set (NO in step S1008), the processing proceeds to step S1009. When the CPU111determines that a continuous reading mode has been set (YES in step S1008), the processing proceeds to step S1010.

In step S1009, the CPU111determines the reading mode to be a DF FCOT mode, and the processing is ended. In step S1010, the CPU111determines the reading mode not to be a DF FCOT mode, and the processing is ended. The CPU111stores the determination result of the FCOT mode in the RAM112.

FIG. 11is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This is an example of scan processing. The processing illustrated in the flowchart is executed by the CPU111of the controller unit100sequentially loading the programs stored in the ROM113and the storage unit114into the RAM112.

When the scan processing is activated, the number of document readings stored in an area (not illustrated) on the RAM112is initialized to 0.

In step S1101, the CPU111operates the document feeding unit280to read a document, and increments the number of document readings stored on the RAM112. The image data301transferred from the scanner unit210by the document reading is stored in an area (not illustrated) secured in the RAM112.

In step S1102, the CPU111refers to the determination result of the FCOT mode stored in the RAM112to determine whether the reading mode is a DF FCOT mode. When the CPU111determines that the reading mode is a DF FCOT mode (YES in step S1102), the processing proceeds to step S1103. When the CPU111determines that the reading mode is not a DF FCOT mode (NO in step S1102), the processing proceeds to step S1108.

In step S1103, the CPU111determines whether the operation is reading of a first sheet, based on the number of document readings stored in the RAM112. When the CPU111determines that the operation is reading of a first sheet (YES in step S1103), the processing proceeds to step S1104. When the CPU111determines that the operation is not reading of a first sheet (the operation is reading of a second or subsequent page)(NO in step S1103), the processing proceeds to step S1108. In step S1104, the CPU111notifies the printer unit300that output preparation has been completed. In step S1105, the CPU111stores, in the storage unit114, the image data301of the document that is stored in an area (not illustrated) secured in the RAM112.

In step S1106, the CPU111determines whether a blank page detection result302transferred from the scanner unit210has been received. When the CPU111determines that a blank page detection result302has been received (YES in step S1106), the processing proceeds to step S1107. When the CPU111determines that a blank page detection result302has not been received (NO in step S1106), the CPU111waits for reception of a determination result.

In step S1107, the CPU111stores the blank page detection result302received in step S1106in the storage unit114. In step S1108, the CPU111compresses the image data301of the document that is stored in the area (not illustrated) secured in the RAM112. In step S1109, the CPU111stores the image data compressed in step S1108in the storage unit114.

In step S1110, the CPU111determines whether a blank page detection result302transferred from the scanner unit210has been received. When the CPU111determines that a blank page detection result302has been received (YES in step S1110), the processing proceeds to step S1111. When the CPU111determines that a blank page detection result302has not been received (NO in step S1110), the CPU111waits for reception of a determination result. In step S1111, the CPU111stores the blank page detection result302received in step S1110in the storage unit114.

In step S1112, the CPU111determines whether the operation is reading of a first sheet, based on the number of document readings stored in the RAM112. When the CPU111determines that the operation is reading of a first sheet (YES in step S1112), the processing proceeds to step S1113. When the CPU111determines that the operation is not reading of a first sheet (NO in step S1112), the processing proceeds to step S1114. In step S1113, the CPU111notifies the printer unit300that output preparation has been completed.

In step S1114, the CPU111determines whether reading of all the documents placed on the document feeding unit280has ended. When the CPU111determines that reading of all the documents placed on the document feeding unit280has not ended (NO in step S1114), the processing returns to step S1101to read a next document. When the CPU111determines that reading of all the documents placed on the document feeding unit280has ended (YES in step S1114), the processing is ended.

FIG. 12is a flowchart illustrating a method for controlling the image forming apparatus according to the present exemplary embodiment. This is an example of print processing. The processing illustrated in the flowchart is executed by the CPU111of the controller unit100sequentially loading the programs stored in the ROM113and the storage unit114into the RAM112.

When the print processing is activated, the CPU initializes the number of output sheet feedings stored in an area (not illustrated) on the RAM112to 0.

In step S1201, the CPU111activates a printer engine in order to increase a temperature of the fixing unit327. In step S1202, the CPU111feeds an output sheet from the sheet feeding source referred to in the determination in step S1003and increments the number of sheet feedings stored in the RAM112.

In step S1203, the CPU111refers to the determination result of the FCOT mode stored in the RAM112to determine whether a reading mode is a DF FCOT mode. When the CPU111determines that the reading mode is a DF FCOT mode (YES in step S1203), the processing proceeds to step S1204. When the CPU111determines that the reading mode is not a DF FCOT mode (NO in step S1203), the processing proceeds to step S1208.

In step S1204, the CPU111determines whether the fed sheet is a first output sheet, based on the number of sheet feedings stored in the RAM112. When the CPU111determines that the fed sheet is a first output sheet (YES in step S1204), the processing proceeds to step S1205. When the CPU111determines that the fed sheet is not a first output sheet (NO in step S1204), the processing proceeds to step S1208. In step S1205, the CPU111executes printing by using the uncompressed image data stored in the RAM112in step S1105.

In step S1206, the CPU111determines whether the output image data is a blank page, based on the blank page detection result302stored in the storage unit114in step S1107. When the CPU111determines that the output image data is a blank page (YES in step S1206), the processing proceeds to step S1207. When the CPU111determines that the output image data is not a blank page (NO in step S1206), the processing proceeds to step S1211.

In step S1207, since the output is a blank page output, the CPU111executes control so as not to perform charging processing at a charging device such as a charging counter or a coin vendor.

In step S1208, the CPU111identifies a page to be printed on the output sheet fed in step S1202among pages stored in the storage unit114, and determines whether the image data is a blank page, based on the blank page detection result stored in step S1111. When the CPU111determines that the image data is a blank page (YES in step S1208), the processing proceeds to step S1212. When the CPU111determines that the image data is not a blank page (NO in step S1208), the processing proceeds to step S1209.

In step S1209, the CPU111reads the image data compressed in step S1108and stored in step S1109, from the storage unit114into the RAM112. In step S1210, the CPU111decompresses the compressed image data read into the RAM112and prints the decompressed data. In step S1211, the CPU111executes control to perform charging for the printing, at a charging device such as a charging counter or a coin vendor.

In step S1212, the CPU111determines whether printing of all the images has ended. When the CPU111determines that printing of all the images has ended (YES in step S1212), the processing proceeds to step S1213. When the CPU111determines that printing of all the images has not ended (NO in step S1212), the processing returns to step S1202to print a next image. In step S1213, the CPU111ends the printer engine to end the processing.

By performing aforementioned control, in the image forming apparatus that carries out blank page detection, a time until output of a first sheet (a first copy output time) when copying from the DF can be shortened. Furthermore, when the user performs a FCOT operation after misplacing the front/rear of the document on the DF, charging can be avoided. As a result, a highly convenient image forming apparatus giving no stress to the user can be provided.

Specific exemplary embodiments of the present invention have been described above. However, the present invention is not limited to the above exemplary embodiments.

The respective processes of the present invention can also be achieved by executing software (a program) acquired via a network or various types of storage media by a processing device (CPU or processor) of a personal computer (computer) or the like.

The present invention is not limited to the above exemplary embodiments. Various modifications (including organic combination of exemplary embodiments) can be made based on the gist of the present invention, and these are within the scope of the present invention.

This application claims the benefit of Japanese Patent Application No. 2014-034455 filed Feb. 25, 2014, which is hereby incorporated by reference herein in its entirety.