JP2006327072A - Double-side printer, inspection method for both-side printed matter, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-side printer which can simply and surely perform the constant inspection of the state of double-side printing. <P>SOLUTION: When the double-side printed matter is composed of n (n is a natural number) sheets of printing paper P, mark printing data is merged into original printed-matter data so that marks Ma and Mb for the inspection expressing n kinds of binary-number sequences composed of k terms satisfying the expression, 2<SP>k-1</SP><n≤2<SP>k</SP>(k is a natural number), can be imparted to both front and back sides while satisfying a complementary relationship in each sheet of printing paper P. After the double-side printing using the merged printing data, the respective marks Ma and Mb are synchronously read by a reading part 4, and a OR signal Ss of output signals Sa and Sb is generated. The OR signal Ss is decreased in the presence of the erroneous order of pages or printing misregistration, while it is set constant when a combination of the front and back sides is normal. A status determination part 6 as a sample hold circuit outputs a voltage value V1 when the combination of the front and back sides is normal, and outputs a voltage value V2 in the presence of an error in the order of the pages or the printing misregistration. Thus, the status of the double-side printing can be constantly inspected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for inspecting a duplex printing state in a duplex printing apparatus that performs printing on both sides of a printing sheet.

  Various types of printing apparatuses (double-sided printing apparatuses) that can perform printing on both sides of a printing paper in a series of printing operations are already known (see, for example, Patent Documents 1 to 3). Among these, there is also an apparatus having a function of inspecting whether or not there is a printing misalignment between the front and back surfaces of a printed matter on which double-sided printing has been performed (see, for example, Patent Document 3). Alternatively, an apparatus for inspecting a positional deviation of a printed pattern is also known (see, for example, Patent Document 4).

JP-A-7-228209 JP 2003-63072 A JP-A-9-240120 Japanese Patent Laid-Open No. 5-31885

  There are various modes of printing defects in printed materials, but as unique to printed materials that have been printed on both sides, the misalignment in which the printing positions on the front and back sides are misaligned and the printed contents (printed pages) on the front and back sides are handled correctly. There is a page misalignment. These printing defects may be caused by human error or may be caused by the operation of the printing apparatus, and depending on the factors, they may occur suddenly during printing. In order to perform good duplex printing, it is required to reliably detect the occurrence of printing defects so that appropriate measures can be taken immediately when such printing defects occur. The larger the number of prints, the greater the loss caused by leaving such defective prints. Therefore, it is strongly desired not to cause such defects as much as possible.

  In Patent Document 1, information representing a document to be printed on the back side is printed with a barcode when printing the front side, and the back side printing appropriately corresponding to the front side can be performed by reading the barcode when printing the back side. An apparatus is disclosed. That is, Patent Document 1 discloses a technique for avoiding page misalignment. However, there is no disclosure about a technique for eliminating the positional deviation.

  Patent Document 2 discloses an apparatus that can print on both sides of a long sheet of paper, and marks are printed at regular intervals when the front side is printed, and the back side is prevented from being displaced by reading the marks when printing the back side. Is disclosed. However, there is no disclosure about a technique for eliminating page misalignment.

  In Patent Literature 3, information indicating the print page of each side and the destination of the printed matter is printed as a barcode on both sides of the printed matter, and collated after double-sided printing, so that the printed contents on both sides are consistent. There is disclosed a technique capable of inspecting and invalidating defective printed matter. According to such a technique, it is possible to identify a printed matter in which page misalignment occurs, but it is necessary to add a barcode according to the printing content of each side, and there is a problem that processing becomes complicated. . In addition, there is no disclosure about a technique for eliminating the positional deviation.

  In Patent Document 4, a pattern printed on both sides of a printed material is detected as a transmission image, compared with a standard pattern, an absolute value of a density difference is calculated in pixel units, and whether or not the sum exceeds a reference value. A technique for determining the presence or absence of a pattern shift is disclosed. In order to apply such a technique, it is necessary to obtain a standard pattern in advance. Therefore, it is not realistic to apply this to a multi-page printed material having different printing contents for each page.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a double-sided printing apparatus that can always and simply inspect double-sided printed matter.

  In order to solve the above-mentioned problems, a first aspect of the present invention is a double-sided printing apparatus that performs printing based on print data on both sides of a printing paper by a predetermined printing unit, and is a first that can identify pages on the surface of the printing paper. First granting means for giving the inspection signal generation information, first inspection signal generation means for generating the first inspection signal by reading the first inspection signal generation information, and identifying the page on the back side of the printing paper Second providing means for providing possible second inspection signal generation information, second inspection signal generation means for generating a second inspection signal by reading the second inspection signal generation information, and Determination means for determining the state of double-sided printing based on a second inspection signal, wherein the first and second inspection signal generation information is provided at the time of double-sided printing by the predetermined printing means, and the first And second inspection The signal generation means synchronously reads the first and second inspection signal generation information, and the determination means performs different determination outputs depending on whether the duplex printing is normal or abnormal. Features.

  A second aspect of the invention is the duplex printing apparatus according to the first aspect, wherein the first inspection signal and the second inspection signal are complementary to each other in the first and second inspection signal generation means. The first and second inspection signal generation information is given to the printing paper so as to be generated as a binarized signal, respectively.

  The invention of claim 3 is the double-sided printing apparatus according to claim 2, further comprising a logical sum signal generating means for generating a logical sum signal of the first and second inspection signals, wherein the determining means is When the logical sum signal is constant, it is determined that double-sided printing is normally performed.

  According to a fourth aspect of the present invention, there is provided the double-sided printing apparatus according to the third aspect, wherein the gate having the same level as the binarized signal while the first and second inspection signal generation information is not read. Gate signal generation means for generating a signal is further provided, wherein the logical sum signal generation means generates a logical sum signal of the first and second check signals and the gate signal.

  The invention according to claim 5 is the double-sided printing apparatus according to claim 3 or 4, wherein the determination unit electrically holds a determination output when the double-sided printing is abnormal for a predetermined time. Are further provided.

  The invention according to claim 6 is the double-sided printing apparatus according to claim 2, and stores grant information indicating a grant status of the first or second inspection signal generation information in the first or second grant unit. A storage unit, wherein the determination unit generates a reference signal based on the given information, and determines the duplex printing state by comparing the first and second inspection signals with the reference signal. It is characterized by.

  A seventh aspect of the present invention is the double-sided printing apparatus according to any one of the first to sixth aspects, wherein the predetermined printing unit is also the first and second providing units, and the first and second The data for giving the inspection signal generation information is synthesized with the print data in advance, and the predetermined printing unit performs printing based on the synthesized print data, thereby generating the first and second inspection signals. It is characterized by giving information.

  The invention according to claim 8 is a method for inspecting a double-sided printed matter printed by a double-sided printing apparatus based on print data, wherein first inspection signal generation information for identifying a page is attached to the surface of a printing paper. 1 applying step, a first inspection signal generating step of generating the first inspection signal by reading the first inspection signal generation information by a predetermined first reading means, and a first page capable of identifying the page on the back surface of the printing paper A second application step of providing the second inspection signal generation information, a second inspection signal generation step of generating the second inspection signal by reading the second inspection signal generation information by a predetermined second reading means, A logical sum signal generation step of generating a logical sum signal of the first and second inspection signals by the generation means, and a determination step of determining a duplex printing state based on the logical sum signal, First and second inspection signals The generation information is given at the time of duplex printing, and the first and second inspections are performed so that the first inspection signal and the second inspection signal are generated as binary signals complementary to each other. Signal generation information is given to the printing paper, the first and second inspection signal generation information is synchronously read in the first and second inspection signal generation steps, and the logic is determined in the determination step. When the sum signal is constant, it is determined that double-sided printing is normally performed.

  The invention of claim 9 is the double-sided printed matter inspection method according to claim 8, wherein, in the logical sum signal generation step, the first and second inspection signal generation information is not to be read. Is characterized in that a predetermined generation means generates a gate signal at the same level as the binarized signal and generates a logical sum signal of the first and second inspection signals and the gate signal.

  A tenth aspect of the invention is the double-sided printed matter inspection method according to the eighth or ninth aspect, wherein the determination step uses a predetermined holding means to electrically output a determination output when the double-sided printing is abnormal. And a holding step for holding for a predetermined time.

  The invention of claim 11 is a method for inspecting a double-sided printed matter printed by a double-sided printing apparatus based on print data, the first providing step of giving first inspection signal generation information to the surface of the printing paper; A first inspection signal generation step of generating the first inspection signal by reading the first inspection signal generation information by a predetermined first reading means; and a second inspection signal generation information for giving the second inspection signal generation information to the back surface of the printing paper. 2 applying step, a second inspection signal generating step of generating a second inspection signal by reading the second inspection signal generation information by a predetermined second reading means, and the first or second applying step. Based on the storage step of storing the application information indicating the application status of the first or second inspection signal generation information in a predetermined storage means, and the state of double-sided printing based on the first and second inspection signals and the reference signal Judge to judge The first and second inspection signal generation information is given during double-sided printing, and the first inspection signal and the second inspection signal are respectively generated as binary signals complementary to each other. As described above, the first and second inspection signal generation information is given to the printing paper, and the first and second inspection signal generation information is read in the first and second inspection signal generation steps. In the determination step, a reference signal is generated based on the given information by a predetermined generation unit, and double-sided printing is performed by comparing the reference signal with the first and second inspection signals. The state is determined.

  A twelfth aspect of the present invention is the double-sided printed matter inspection method according to any one of the eighth to eleventh aspects, wherein data for giving the first and second inspection signal generation information is the print data. The first and second inspection signal generation information is provided when the duplex printing apparatus performs printing based on the print data after the synthesis in the synthesis step. Features.

  According to a thirteenth aspect of the invention, when executed in a computer, the computer is caused to function as control means of the double-sided printing apparatus according to any one of the first to seventh aspects.

  According to the first to thirteenth aspects of the present invention, it is possible to inspect the presence or absence of a page shift or a position shift in the double-sided printed material in a simple manner.

  In particular, according to the inventions of claims 2 to 6 and claims 8 to 11, it is easy to determine whether or not pages in a front-and-back relation in a double-sided printed matter correspond correctly.

  In particular, according to the inventions of claims 3 to 5 and claims 8 to 10, it is possible to detect whether or not there is an abnormality in the state of duplex printing as long as the logical sum signal is monitored. Therefore, it is possible to easily grasp that a page shift or a position shift has occurred in the double-sided printed material.

  In particular, according to the fourth and ninth aspects of the present invention, even when the inspection signal generation information is given to only a part of the printing paper, the logic is used only when the page deviation or the position deviation occurs. Since the sum signal fluctuates, there is no need to control the reading operation according to the application state of the inspection signal generation information.

  In particular, according to the inventions of claims 5 and 10, the operator can more reliably recognize that there is an abnormality in the double-sided printing.

  In particular, according to the inventions of claims 6 and 11, since the double-sided printing state is determined based on the inspection signal generation information actually given to the printing paper, page misalignment or misalignment occurs in the double-sided printed matter. You can be sure of this.

<First Embodiment>
<Principle of state inspection for double-sided printing>
FIG. 1 is a diagram for explaining the principle of the inspection of the duplex printing state performed in the first embodiment of the present invention. FIG. 1A shows a state in which an inspection mark Ma and an inspection mark Mb are provided at predetermined positions on the front surface Pa and the back surface Pb of the printing paper P, respectively. These are used to print the print data obtained by combining predetermined print data for printing with the print data for obtaining the original print image of each side, so that the original print image is also formed at a predetermined position on the printing paper. It has been done.

  Each of the inspection marks Ma and Mb is configured by appropriately placing a printed rectangular block and a blank (non-printed) rectangular block adjacent to each other. This can be regarded as a binary number sequence marked by considering a portion with printing as “1” and a portion without printing as “0”. That is, in the inspection mark Ma, it can be seen that a sequence of “1, 0, 1, 0” is expressed from the left side of the drawing. If the inspection mark Ma is read by a predetermined reading means such as a photo sensor during the conveyance of the printing paper, an array corresponding to “1” and “0” is turned on / off of the output signal from the reading means. It is possible to correspond to off control. Specifically, it is possible to output an output signal Sa (a voltage value in an on state is V) as shown in FIG. That is, the inspection mark Ma can be regarded as a signal generation source that outputs a binarized signal from the reading unit. Since the arrangement position of the inspection mark Ma on the printing paper is known, it is possible to perform such reading in accordance with the timing at which the inspection mark Ma passes through the reading means during conveyance of the printing paper.

  Similarly, for the inspection mark Mb, a sequence of “0, 1, 0, 1” in which “0” and “1” are inverted for each term constituting the sequence represented by the inspection mark Ma. Can be seen as being expressed. From this inspection mark Mb, an output signal Sb having the same voltage value V as that of the output signal Sa can be outputted as shown in FIG.

  In the present embodiment, as in the case shown in FIG. 1, one of all the terms is between the number sequence expressed by the inspection mark Ma and the number sequence expressed by the inspection mark Mb. If the relationship that “1” is the other is “0” is satisfied, the inspection marks Ma and Mb, the numerical sequence represented by them, and the inspection marks Ma and Mb are read. The output signals Sa and Sb to be output are referred to as “complementary relationship”.

  Next, considering the case where the reading of the inspection mark Ma and the inspection mark Mb is performed in synchronization, in this case, if a logical sum is taken for the signals output from the respective reading means, FIG. As shown in (d), a constant OR signal Ss with a voltage value level of V is obtained. In other words, when the output signals Sa and Sb, which are binary signals having a complementary relationship, are output in synchronization, the logical sum signal Ss is obtained as a signal having a constant level.

  For this reason, when performing double-sided printing, it is necessary to preliminarily provide inspection marks that have a complementary relationship on the front and back sides of pages that are related to the front and back sides of printing paper. After that, it is possible to determine the duplex printing state simply by monitoring the logical sum signal. Specifically, if there is no page shift or position shift in double-sided printing, the logical sum signal Ss becomes a constant level signal, but if any shift occurs, the logical sum signal Ss changes. Become. In this embodiment, this principle is used to determine whether double-sided printing is normally performed. In this regard, further description will be given while showing different inspection mark modes.

  FIG. 2 illustrates a case where the “1” state and the “0” state are expressed by different print patterns. That is, the case where “1” and “0” are defined in units of two blocks is shown. Specifically, a pattern with printing on the front side represents “1”, and a pattern with printing on the rear side represents “0”.

  In the case of FIG. 2A, the inspection mark Ma on the front surface represents a sequence of numbers “1, 0, 0, 1” and the inspection mark Mb on the back surface represents a sequence of numbers “0, 1, 1, 0”. Will do. Also in this case, since the inspection marks on the front and back surfaces are given so as to satisfy a complementary relationship, the OR signal Ss obtained when these readings are performed synchronously is shown in FIG. As in the case of, a signal having a constant level is obtained. Unlike the case of FIG. 1 in which “0” is represented by only blanks, the pattern shown in FIG. 2 always prints a block regardless of whether it is “1” or “0”. It can be said that the reliability is high enough to distinguish between the case of mistake and the case of “0”.

  On the other hand, FIG. 2B shows a case where the inspection marks on the front and back surfaces do not have a complementary relationship. The inspection mark Ma on the front surface represents a sequence of numbers “1, 0, 0, 1”, whereas the inspection mark Mb on the back surface represents a sequence of numbers “1, 1, 0, 0”. In such a case, even if reading is started synchronously, the OR signal Ss is not constant, and an error state in which the output is 0 (voltage value) is intermittently generated. Even if it is determined that the inspection marks having the complementary relationship are attached to the pages correctly in the front and back relation, the output of the logical sum signal Ss may not be constant in this way. This means that page misalignment has occurred in the printed matter for some reason.

  Further, FIG. 2C shows a sequence in which the inspection mark Ma on the front surface is “1, 0, 0, 1” and a sequence in which the inspection mark Mb on the back surface is “0, 1, 1, 0”. This represents a case where the readings of the inspection marks on both sides are deviated, although the relationship between the sequences is complementary. Also in this case, the logical sum signal Ss is not constant, and an error state in which the output is 0 occurs intermittently. That is, an error state occurs intermittently even when the distance Δ is shifted in printing on either the front or back side.

Generally speaking, when one unit of a double-sided printed material is composed of n (n is a natural number) printing paper, n types of k terms including 2 ^k−1 <n ≦ 2 ^k (k is a natural number) are satisfied. It is only necessary that the inspection mark representing the binary number sequence is provided on the front and back surfaces of each printing paper while satisfying the complementary relationship as described above.

For example, in the case of a printed matter having 200 pages on both sides, 2 ⁷ <200 ≦ 2 ⁸ , and therefore 100 sets of inspection marks that represent binary sequences of 8 terms that are complementary to each other ( (200 types). This is a binary number sequence corresponding to decimal numbers 1 to 100 “0, 0, 0, 0, 0, 0, 0, 1” to “0, 1, 1, 0, 0, 1, 0, 0”. ”For the front side and“ 1,1,1,1,1,1,1,0 ”corresponding to decimal numbers 254 to 155 are also provided for the back side. This means that inspection marks Mb expressing “1, 0, 0, 1, 1, 0, 1, 1” may be prepared and given sequentially. This means that for a printed matter of 254 pages or less, all pages can be identified by a binary number sequence consisting of 8 terms. However, in reality, it is considered extremely rare that a page shift of 254 pages or more occurs. Therefore, even in the case of a printed matter having more pages than that, that is, a printed material including 128 or more printing sheets, the 128th sheet In addition, an inspection mark corresponding to “0, 0, 0, 0, 0, 0, 0, 1” is provided on the front surface, and “1, 1, 1, 1, 1, 1, 1” is provided on the back surface. , 0 "can be provided in practice if it is provided with an inspection mark.

  In any case, the mark print data is combined with the original print data so that the inspection mark satisfies such a relationship and is additionally printed on each page (on the front and back surfaces of all printed matter). Double-sided printing is performed using subsequent print data. Then, reading of the inspection marks attached to both sides after printing is performed synchronously, and the printing state is determined based on the logical sum signal of the signals obtained from each.

  Then, by providing the inspection mark as described above, it is easy to determine whether or not the pages having the front and back relationship are correctly associated with each other in the printed matter after double-sided printing. If the logical sum signal obtained for the printed material after double-sided printing is constant, it can be determined that normal double-sided printing is being performed, with the front and back sides correctly responding and no misalignment. If the signal intermittently becomes 0, it is determined that a page shift or a print position shift has occurred.

  In other words, the inspection marks previously provided on the front and back surfaces of the printed matter are synchronously read by a predetermined reading sensor to generate inspection signals for each of them, and the logical sum signal is monitored to thereby detect the double-sided printed matter. This can be detected when any misalignment such as page misalignment or misalignment occurs in the printing state.

<Device configuration>
FIG. 3 is a diagram illustrating a schematic configuration of the double-sided printing apparatus 10 according to the first embodiment. The duplex printing apparatus 10 is configured to perform printing on both sides of a printing sheet and to determine whether the duplex printing state is appropriate based on the principle described above.

  As shown in FIG. 3, the double-sided printing apparatus 10 is roughly divided into a controller 1 and a main body 2 due to its configuration.

  The controller 1 is for controlling the entire processing of the duplex printing apparatus 10. FIG. 4 is a diagram schematically illustrating the configuration of the controller 1. The controller 1 can be realized by a general computer. The controller 1 includes an operation unit 11 including a mouse and a keyboard for an operator to input various instructions, a display unit 12 such as a display, a hard disk, and the like, and a program for causing the computer to function as the controller 1 13p, a media reader that reads / writes data between the storage unit 13 for storing print data to be processed and various portable recording media such as a DVD-RAM / RW and a CD-RW A communication unit 15 as an interface for exchanging data with other devices on the network when the controller 1 is connected to a network (not shown); CPU 16a, ROM 16b, and RAM 16c, which will be described later. Mainly and a control unit 16 for realizing the functions.

  In the controller 1, a so-called GUI (Graphical User Interface) capable of performing processing while displaying the operation content through the operation unit 11 and the processing status of various processes on the display unit 12 is controlled. It is preferably realized by the functions of the unit 16, the operation unit 11, and the display unit 12. In such a case, processing in each unit described later realized in the control unit 16 is also performed using this GUI as necessary.

  The controller 1 obtains print data to be printed from the outside, performs various data processing (data conversion) as necessary, and serves for printing processing in the main body unit 2. FIG. 5 is a diagram for explaining functions realized in the control unit 16 of the controller 1. In the control unit 16, by executing a predetermined program 13 p stored in the storage unit 13, the print data acquisition unit 21, the print data conversion unit 22, and the data are processed by the operations of the CPU 16 a, the ROM 16 b, and the RAM 16 c. The synthesizing unit 23, the print execution instructing unit 24, and the warning processing unit 29 are mainly realized.

  The print data acquisition unit 21 acquires print data DP such as layout data in which contents related to the layout of the printed material are described from the outside of the duplex printing apparatus 10. When the print data DP is acquired by the print data acquisition unit 21 if the print data DP is recorded on a predetermined portable recording medium, the print data DP is read from the recording medium by the operation of the R / W unit 14. Is realized. On the other hand, when acquiring from a predetermined external device via a network, it is realized by accessing the external device via the communication unit 15. The double-sided printing apparatus 10 itself may have a printed matter layout processing function and be configured to generate print data.

  The print data conversion unit 22 performs processing for converting the acquired print data DP into data in a format that can be processed by the main body unit 2. The specific processing contents vary depending on the configuration of the main body unit 2. For example, rasterization processing, screening processing, color space conversion processing, and the like are performed as necessary. The print data conversion unit 22 is configured to be able to perform these processes.

  The data synthesizing unit 23 performs processing for synthesizing the mark print data DM for printing the inspection mark used for the inspection of the printing state of the double-sided printing with the acquired print data DP. The mark print data DM is stored in the storage unit 13 in advance, and is appropriately read out during the composition process.

  Here, the mark print data DM is data for providing 254 types of inspection marks corresponding to binary numbers of 8 terms on the front and back surfaces of the printing paper. By giving this inspection mark, the front and back surfaces of 127 printing sheets at the maximum (that is, 254 pages) can be uniquely identified. In the printing process, the print data is synthesized so that a test mark having a complementary relationship is given to each page that is (should) have a front / back relationship on one printing sheet. Become.

  In addition to the rectangular block described above, various shapes can be applied to the specific shape of the inspection mark depending on the content of the printed matter, the size of the printing paper, and the like. May be selected as appropriate. Such variations of the inspection mark will be described in a later-described modification.

  Further, the position of each inspection mark on the printing paper is premised on that the reading unit 4 to be described later can be read, but it depends on the contents of the printed matter, the size of the printing paper, the type of the mark, and the like. Accordingly, it may be determined appropriately. Also in this case, it may be possible to select appropriately by the operation of the data synthesis unit 23.

  FIG. 6 is a diagram illustrating an arrangement position on the printing paper P with respect to the inspection marks Ma and Mb in a form in which rectangular blocks are arranged in a line. In the case of the inspection mark of this aspect, it can be arranged so as not to stand out, for example, at the end of the printing paper so as not to obstruct the main content expression of the printed matter. In addition, there is an advantage that reading can be sequentially performed while being transported by arranging it in accordance with the transport direction of the printing paper. Also in this case, as shown in FIG. 6 (a), the inspection marks Ma and Mb may be provided at the same position on the front and back surfaces of the printing paper, or as shown in FIG. 6 (b). It may be given to the position. In particular, when there is a risk of show-through, it is preferable to take the latter mode in order to prevent erroneous recognition.

  In response to a print execution instruction given from the operator of the duplex printing apparatus 10 through the operation unit 11, the print execution instruction unit 24 is executed to execute printing on the print data DP in which the mark print data DM is combined. It is responsible for processing the print data DP together with the instruction signal to the main unit 2.

  In response to the determination output from the state determination unit 6 described later that there is an abnormality in double-sided printing, the warning processing unit 29 causes, for example, a predetermined warning display to be displayed on the display unit 12 or a warning (not shown). It is responsible for processing to turn on or blink the lamp or to generate a predetermined warning sound by a predetermined means (not shown).

  The main body 2 is a mechanism that performs duplex printing based on the print data DP in response to a print execution instruction from the controller 1 or inspects printed matter. Substantially, the printing mechanism 3, the reading unit 4, the logical operation unit 5, and the state determination unit 6 are mainly configured. FIG. 7 is a diagram specifically showing the relationship of the components related to the double-sided printing inspection in the present embodiment.

  The printing mechanism 3 plays a role of forming a print image on the printing paper P based on a print execution instruction from the controller 1. The printing mechanism 3 mainly includes a front surface image forming unit 31a, a back surface image forming unit 31b, a print control unit 32, and a paper detection unit 33.

  The front surface image forming unit 31a and the back surface image forming unit 31b are responsible for forming print images on the front surface Pa and the back surface Pb of the printing paper P, respectively. In FIG. 3, although the aspect which forms a printing image by the transfer of the ink from a roller is shown simply, this is only an illustration to the last. For example, the image forming may be performed using an inkjet method, an electrophotographic method, or other methods. In the present embodiment, in addition to the printed image constituting the substantial content of the printed matter, the inspection marks Ma and Mb used when inspecting the printing state on both sides are also printed on each of the front and back surfaces. Become.

  The print control unit 32 interprets the print data DP delivered from the controller 1, and performs image forming operations of the front surface image forming unit 31a and the back surface image forming unit 31b, a printing paper transporting operation by a transporting mechanism (not shown), and the like. Take control. For example, if the image is formed by ink transfer using a roller, the rotation operation of the roller is controlled. If the ink jet method is employed, the ink cartridge moving operation and ink ejection operation are controlled. In the case of the electrophotographic system, the exposure operation to the photoconductor and the transfer operation from the transfer drum to the printing paper are controlled.

  The paper detection unit 33 is provided for detecting the edge of the print paper P that is conveyed for forming a print image. The paper detection unit 33 is realized by an optical sensor, for example. In such a case, the printing paper P is detected using the fact that the amount of reflected light of the light emitted from the optical sensor differs depending on the presence or absence of the printing paper being conveyed. The detection result by the paper detection unit 33 is used to specify the timing of printing image formation by the front surface image forming unit 31a and the back surface image forming unit 31b. Alternatively, it is also used for double-sided printing inspection described later.

  The reading unit 4 is a reading unit that reads inspection marks printed at predetermined positions on both sides of the printing paper P. The reading unit 4 includes a front surface reading sensor 4a that detects the inspection mark Ma on the front surface of the printing paper P, and a back surface reading sensor 4b that reads the inspection mark Mb on the back surface. Both the front surface reading sensor 4a and the back surface reading sensor 4b can be configured by a known so-called photosensor. For example, the surface reading sensor 4a shown in FIG. 7 inspects the surface Pa of the printing paper P on which a printed image is formed and conveyed from a light source (not shown) built in the main body 41a through the optical fiber 42a-1. In addition to irradiating light, the reflected light can be received by the light receiving unit built in the main body 41a through the optical fiber 42a-2. Then, an output that is a binarized signal depends on whether or not the amount of light received from the inspection mark Ma when the inspection mark Ma is irradiated with the inspection light exceeds a predetermined reference value. The on / off state of the signal Sa is determined. The main body portion 41b of the back surface reading sensor 4b and the optical fibers 42b-1 and 42b-2 are also configured to perform the same function. That is, the on / off state of the output signal Sb is determined based on the inspection mark Mb on the back surface. Preferably, both of the front side reading sensor 4a and the back side reading sensor 4b can appropriately adjust the reference value of the amount of received light according to the printing density of the inspection mark and the type of printing paper.

  The logical operation unit 5 generates a logical sum signal Ss of the output signal Sa output from the front surface reading sensor 4a and the output signal Sb output from the back surface reading sensor 4b by logical operation by the OR circuit 51. According to the principle described above, it is possible to determine whether double-sided printing is normal or not based on whether or not the logical sum signal Ss is constant, but in the present embodiment, a gate signal generation source is further provided. 52, the gate signal Sg is generated, the logical sum of the logical sum signal Ss and the gate signal is further calculated in the OR circuit 53, and based on the determination signal Sj, double-sided printing in the state determination unit 6 described below is performed. The state is determined.

  FIG. 8 is a diagram for explaining the reason for using such a determination signal Sj. 8A shows an output signal Sa output from the front surface reading sensor 4a by reading the inspection mark Ma given to the front surface Pa of the printing paper P, and FIG. 8B gives it to the back surface Pb. An output signal Sb output from the back surface reading sensor 4b by reading the inspection mark Mb, and these logical sum signals Ss are exemplarily shown in FIG. 8C. However, the inspection marks Ma and Mb are assumed to exist only in a part of the sheet range in the reading direction. Further, it is assumed that reading by the reading unit 4 is performed from the left side to the right side of the drawing.

  In such a case, if reading is performed for a range where there is no inspection mark, only an off-state signal with an output value of zero is output on both the front and back surfaces, so the output of the logical sum signal is also zero. become. In the above description, in order to avoid this, a mode is described in which reading is performed only while the inspection mark passes the reading position. However, this is the case for both the front surface reading sensor 4a and the back surface reading sensor 4b. Since frequent switching between the reading operation state and the stop state is required, the control is complicated.

  Therefore, in the present embodiment, instead of such a mode, the front side reading sensor 4a and the back side reading sensor 4b are always in an operating state, while the inspection mark does not exist (should be) in the printing paper. Is passing through both sensors, a gate signal Sg having the same output value (voltage value V) as the logical sum signal in the ON state is generated, and a logical sum is obtained between the logical sum signal Ss in the OR circuit 53. Let it be calculated. In this way, even when a portion of the printing paper without the inspection mark passes through the reading unit 4, a signal having the same output value as the output value of the logical OR signal Ss in a normal state is output. Therefore, as long as the gate signal Sg is turned on / off, an error state can be output only when there is a problem in double-sided printing on the front and back surfaces without controlling the on / off of the reading operation by the reading unit 4. It becomes like this. Since the distances d1 and d2 between the paper edge and the inspection mark and the conveyance speed of the printing paper are known, the on / off switching of the gate signal Sg indicates the timing at which the paper detection unit 33 detects the paper edge. As a standard, it can be performed accurately.

  The state determination unit 6 performs processing for determining whether or not the duplex printing state is normal based on the determination signal Sj output from the logic operation unit 5, more specifically, improper duplex printing is performed. In such a case, it is necessary to carry out processing necessary to ensure that the operator of the duplex printing apparatus 10 recognizes that fact. The state determination unit 6 is practically realized by a so-called sample hold circuit. That is, when the determination signal Sj output from the logic operation unit 5 is a signal having a voltage value V indicating a normal state, the diode 61 is not turned ON, and the comparator 62 at the next stage has a higher potential than the reference voltage Vref. Therefore, a low-level determination output is made (voltage value V1). On the other hand, when the determination signal Sj is 0, the diode 61 is turned on and the capacitor 63 is charged, so that the determination output in the comparator 62 is electrically held at a high level (voltage value V2) for a predetermined time. Become. As a result, it is possible to easily detect whether page misalignment or position misalignment has occurred in double-sided printing.

  When a high-level determination output is made in this way, the warning processing unit 29 of the controller 1 that has received the output signal performs some kind of warning processing as described above. As a result, the operator of the duplex printing apparatus 10 can reliably recognize that page misalignment or misalignment has occurred in duplex printing.

  As described above, according to the present embodiment, in the case of double-sided printing, an inspection mark that provides a complementary relationship is assigned to each page that has a front-back relationship on one printing paper, After printing, if page misalignment or misalignment occurs in double-sided printing by detecting the logical sum signal of the binary signal generated by reading the inspection marks attached to the front and back surfaces, and monitoring the output This can be easily detected. That is, the double-sided printed material can be inspected by a simple and reliable method.

<Second Embodiment>
In the above-described embodiment, the front and back surfaces of the printing paper are provided with inspection marks having a complementary relationship, and the state of double-sided printing is determined by using the logical sum signal of the binary signals generated by reading these marks. Although it is an aspect to determine, the aspect of the process which determines the state of double-sided printing after reading the inspection mark is not limited to this. A processing mode different from that of the first embodiment will be described as a second embodiment. The components of the double-sided printing apparatus according to the present embodiment are generally the same as those of the double-sided printing apparatus 10 according to the first embodiment. Therefore, unless otherwise specified, the same reference numerals are given and the following description will be given. Is omitted.

  FIG. 9 is a diagram for explaining functions realized in the control unit 16 of the controller 1 according to the second embodiment. In the present embodiment, in addition to each unit shown in FIG. 5, the first point is that the mark determination unit 25 is realized and the mark determination data DR is stored in the storage unit 13. This is different from the embodiment. FIG. 10 is a diagram specifically showing the relationship between the components related to the double-sided printing inspection in the present embodiment. In the present embodiment, the inspection marks Ma and Mb previously given to both surfaces of the printing paper P are read by the reading unit 4 until the output signals Sa and Sb are output, as in the first embodiment. Similar processing is performed.

  In the present embodiment, the output signals Sa and Sb obtained in this way are transmitted to the mark determination unit 25. The mark determination unit 25 compares these output signals Sa and Sb with a reference signal Sr generated based on the mark determination data DR. Whether or not there is an abnormality in the double-sided printing state is determined based on the collation result.

  Here, the mark determination data DR is data describing which inspection mark is assigned to which page by combining the mark print data DM in the data combining unit 23. The mark determination data DR is, for example, a combination of a page number of all the surfaces of the printing paper constituting the printed matter and a binary number sequence corresponding to the inspection mark given to each page in a predetermined data format. It is composed by describing with. The mark determination unit 25 generates a reference signal Sr for each page based on the mark print data DM.

  If the reference signal Sr is generated in this way, the reference signal Sr for a certain page is obtained by actually reading the inspection mark Ma for the page by the surface reading sensor 4a as long as printing is properly performed. It coincides with the output signal Sa to be output. Further, since the inspection marks on the front and back surfaces should be provided so as to be complementary to each other, the level of the output signal Sb output from the back surface reading sensor 4b for the page corresponding to the back surface of the page is inverted. (Corresponding to switching the state of “1” and the state of “0”) matches the reference signal Sr.

  The mark determination unit 25 determines the duplex printing state based on this principle. More specifically, each time the inspection marks Ma and Mb pass through the reading unit 4, the front side reading sensor 4a and the back side reading sensor 4b read them and output the output signals Sa and Sb. Based on the description of DR, a reference signal Sr for one page is sequentially generated and collated with the output signals Sa and Sb (the output signal Sb is inverted and collated). When the signals coincide with each other on both the front and back surfaces, it is in a normal state and a low-level determination output (voltage value V1 ') is performed. If there is no coincidence in at least one of them, a high level determination output (voltage value V2 ') is performed because some sort of occurrence has occurred.

  When the mark determination unit 25 outputs a high-level determination output, the warning processing unit 29 of the controller 1 that receives the output signal performs some warning processing in the same manner as in the first embodiment. That is, also in the present embodiment, the operator of the double-sided printing apparatus 10 can reliably recognize that a page shift or a position shift has occurred in double-sided printing. That is, the double-sided printed material can be inspected at all times by a simple and reliable method.

<Modification>
As described above, various types of inspection marks can be applied. FIG. 11 and FIG. 12 are diagrams illustrating another aspect of the inspection mark. The inspection mark Ma shown in FIG. 11A and Mb shown in FIG. 11B can generate a binarized signal in the same manner as described above by a combination of key-shaped unevenness. That is, since the combination of these irregularities is also complementary, the same effect as the above-mentioned bite can be obtained by reading the front surface along the arrow AR1 and reading the rear surface along the arrow AR2. Can do. Further, the inspection mark Ma shown in FIG. 12A and the Mb shown in FIG. 12B are both two-dimensional codes also called Carla code (registered trademark), but the inspection marks Ma and Mb are also complementary. This also makes it possible to generate a binarized signal in the same manner as described above.

  In the above-described embodiment, when “1” and “0” are expressed by a rectangular block, the printed portion and the unprinted portion are shown to have the same size. Is not an essential requirement. Rather, in consideration of printing accuracy, it may be made longer than a portion where there is no printed portion. FIG. 13 is a diagram illustrating such a case. In such a case, since the portion with the inspection mark Ma printing on the front surface and the portion with the printing of the inspection mark Mb on the back surface overlap by the length w, even if a printing error of this length w or less occurs, This does not affect the determination of the duplex printing state, and the cost for improving the inspection accuracy can be reduced.

  In the above-described embodiment, the mode in which the reading unit optically reads the inspection mark has been described. However, a mode in which this is magnetically read may be used. However, in this case, the double-sided printing apparatus is configured so that the inspection mark is magnetically readable.

  In the second embodiment described above, based on the combination of the page numbers of all the surfaces of the printing paper constituting the printed matter and the binary number sequence corresponding to the inspection mark assigned to each page. However, instead of this, the mark determination data DM is generated based on the combination of the page number on the back side and the binary number sequence corresponding to the inspection mark assigned to each page. It may be an embodiment that generates DM. In this case, when determining the duplex printing state using the reference signal Sr, the output signal Sb for the back side is used as it is, and the output signal Sa for the front side is inverted and used.

It is a figure for demonstrating the principle of the state inspection of double-sided printing made in 1st Embodiment. It is a figure which illustrates the case where a binary number sequence is expressed by the difference in a printing pattern. 1 is a diagram showing a schematic configuration of a double-sided printing apparatus 10 according to a first embodiment. FIG. 2 is a diagram schematically showing a configuration of a controller 1. It is a figure for demonstrating the function implement | achieved in the control part 16 which concerns on 1st Embodiment. FIG. 6 is a diagram illustrating an example of arrangement positions of inspection marks Ma and Mb on a printing paper P. It is a figure which shows concretely about the relationship of the component which concerns on the inspection of double-sided printing in 1st Embodiment. It is a figure for demonstrating the reason for using signal Sj for determination. It is a figure for demonstrating the function implement | achieved in the control part 16 which concerns on 2nd Embodiment. It is a figure which shows concretely about the relationship of the component which concerns on the inspection of double-sided printing in 2nd Embodiment. It is a figure which illustrates the other aspect of the mark for a test | inspection. It is a figure which illustrates the other aspect of the mark for a test | inspection. It is a figure which illustrates the case where the length of the mark for an inspection is changed with the presence or absence of printing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Controller 2 Main body part 3 Printing mechanism 4 Reading part 4a Front surface reading sensor 4b Back surface reading sensor 5 Logical operation part 6 State determination part 10 Duplex printing apparatus 31a Front surface image formation part 31b Back surface image formation part 32 Print control part 33 Paper detection part 41a Main body part 41b (of the back side reading sensor) Main body part 42a-1, 42a-2 (of the front side reading sensor) Optical fiber 42b-1, 42b-2 Optical fiber 51, 53 (of the back side reading sensor) OR circuit 52 Gate signal generation source DM Mark print data DR Mark determination data Ma, Mb Inspection mark P Printing paper Sa, Sb (from reading sensor) Output signal Sg Gate signal Sj Determination signal Sr Reference signal Ss OR signal

Claims (13)

A double-sided printing apparatus that performs printing based on print data on both sides of a printing paper by a predetermined printing means,
First providing means for providing first inspection signal generation information capable of identifying a page on the surface of the printing paper;
First inspection signal generation means for generating a first inspection signal by reading the first inspection signal generation information;
Second providing means for providing second inspection signal generation information capable of identifying a page on the back surface of the printing paper;
Second inspection signal generation means for generating a second inspection signal by reading the second inspection signal generation information;
Determination means for determining a double-sided printing state based on the first and second inspection signals;
With
The first and second inspection signal generation information is given at the time of double-sided printing by the predetermined printing unit,
The first and second inspection signal generation means synchronously read the first and second inspection signal generation information,
The determination means performs a determination output that differs depending on whether the duplex printing is normal or abnormal.
A double-sided printing apparatus characterized by that. The double-sided printing apparatus according to claim 1,
The first and second inspection signal generation means generates the first and second inspection signals so that the first inspection signal and the second inspection signal are generated as complementary binary signals, respectively. Signal generation information is given to the printing paper,
A double-sided printing apparatus characterized by that. The double-sided printing apparatus according to claim 2,
A logical sum signal generating means for generating a logical sum signal of the first and second inspection signals;
Further comprising
The determination means includes
When the logical sum signal is constant, it is determined that double-sided printing is normally performed.
A double-sided printing apparatus characterized by that. The double-sided printing apparatus according to claim 3,
Gate signal generating means for generating a gate signal of the same level as the binarized signal while the first and second inspection signal generation information is not to be read;
Further comprising
The logical sum signal generating means generates a logical sum signal of the first and second inspection signals and the gate signal;
A double-sided printing apparatus characterized by that. The double-sided printing apparatus according to claim 3 or 4,
The determination means is
A holding means for electrically holding a determination output when the double-sided printing is abnormal;
A double-sided printing apparatus, further comprising: The double-sided printing apparatus according to claim 2,
Storage means for storing grant information indicating the grant status of the first or second test signal generation information in the first or second grant means;
Further comprising
The determination means is
A reference signal is generated based on the given information, and a state of double-sided printing is determined by comparing the first and second inspection signals with the reference signal.
A double-sided printing apparatus. The double-sided printing apparatus according to any one of claims 1 to 6,
The predetermined printing means is also the first and second giving means;
Data for giving the first and second inspection signal generation information is combined with the print data in advance, and the predetermined printing unit performs printing based on the combined print data, thereby the first and second inspection signal generation information are combined. Giving second inspection signal generation information;
A double-sided printing apparatus characterized by that. A method for inspecting a double-sided printed matter printed by a double-sided printing device based on print data,
A first providing step of providing first inspection signal generation information capable of identifying a page on the surface of the printing paper;
A first inspection signal generation step of generating the first inspection signal by reading the first inspection signal generation information by a predetermined first reading unit;
A second providing step of providing second inspection signal generation information capable of identifying a page on the back surface of the printing paper;
A second inspection signal generation step of generating the second inspection signal by reading the second inspection signal generation information by a predetermined second reading unit;
A logical sum signal generating step of generating a logical sum signal of the first and second inspection signals by a predetermined generation means;
A determination step of determining a double-sided printing state based on the logical sum signal;
With
The first and second inspection signal generation information is given at the time of duplex printing,
The first and second inspection signal generation information is given to the printing paper so that the first inspection signal and the second inspection signal are respectively generated as binary signals complementary to each other,
In the first and second inspection signal generation steps, the first and second inspection signal generation information is synchronously read,
In the determination step, it is determined that double-sided printing is normally performed when the logical sum signal is constant.
A method for inspecting double-sided printed matter. A method for inspecting a double-sided printed matter according to claim 8,
In the logical sum signal generation step,
While the first and second inspection signal generation information is not to be read, a predetermined generation unit generates a gate signal having the same level as the binarized signal,
Generating a logical sum signal of the first and second inspection signals and the gate signal;
A method for inspecting double-sided printed matter. A method for inspecting a double-sided printed material according to claim 8 or 9,
The determination step includes
A holding step of electrically holding a determination output when the double-sided printing is abnormal by a predetermined holding unit for a predetermined time;
An inspection method for double-sided printed matter, further comprising: A method for inspecting a double-sided printed matter printed by a double-sided printing device based on print data,
A first providing step of providing first inspection signal generation information on the surface of the printing paper;
A first inspection signal generation step of generating the first inspection signal by reading the first inspection signal generation information by a predetermined first reading unit;
A second providing step of providing second inspection signal generation information on the back surface of the printing paper;
A second inspection signal generation step of generating the second inspection signal by reading the second inspection signal generation information by a predetermined second reading unit;
A storage step of storing in a predetermined storage means grant information indicating a grant status of the first or second inspection signal generation information in the first or second grant step;
A determination step of determining a double-sided printing state based on the first and second inspection signals and the reference signal;
With
The first and second inspection signal generation information is given at the time of duplex printing,
The first and second inspection signal generation information is given to the printing paper so that the first inspection signal and the second inspection signal are respectively generated as binary signals complementary to each other,
In the first and second inspection signal generation steps, the first and second inspection signal generation information is synchronously read,
In the determination step, a reference signal is generated based on the given information by a predetermined generation unit, and the double-sided printing state is determined by comparing the reference signal with the first and second inspection signals. ,
A method for inspecting double-sided printed matter. A method for inspecting a double-sided printed material according to any one of claims 8 to 11,
A combining step of combining the print data with data for providing the first and second inspection signal generation information;
Further comprising
The first and second inspection signal generation information is given by the double-sided printing apparatus performing printing based on the print data after combining by the combining step.
A method for inspecting double-sided printed matter.   A program that, when executed on a computer, causes the computer to function as a control unit of the duplex printing apparatus according to any one of claims 1 to 7.

Images