JP2007182021A - Image storage device, image storage method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize a storage area for storing an image, in a situation that the same document is often printed more than once. <P>SOLUTION: A printer 500 comprises a history image search part 507, a history image registration part 508, and a history image information storage part 509, in addition to a PDL data input part 501 which stores PDL data in a PDL data storage part 502 by receiving them from a host computer 510, a PDL data conversion part 503 which stores image data in an image data storage part 504 by converting the PDL data into the image data, and a printing control part 505 which outputs the image data into a printing engine 506. The search part 507 searches for the storage part 509 by using the received PDL data as a key, and determines whether or not the image data printed from the same document in the past have already been registered. When the image data from the same document have not been registered yet, the registration part 508 registers newly generated image data in the storage part 509. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image storage device that retains a history of a printed document as image data, and more particularly to an image storage device that effectively uses a storage area for storing image data.

As a recent office environment, a large number of devices such as PCs (Personal Computers) and printers are connected to each other via a LAN (Local Area Network) and connected to the outside via the Internet. It is generally done. In such a network-connected office environment, today, there is a problem of leakage of information in which confidential information is stored in a PC and taken out or leaked to the outside through the Internet. Thus, for the purpose of preventing such information leakage, a so-called image log technique has been developed in which a history of image data is left in the printing apparatus even after printing a document or the like (see, for example, Patent Document 1).
The image processing apparatus disclosed in Patent Document 1 stores a printed image as a history in the image forming apparatus itself. The user of the image forming apparatus can specify the model name, serial number, installation location, and the like of the image forming apparatus that is the output destination of the printed matter that has been problematic due to unauthorized use by searching the history. It becomes possible. In the embodiment of Patent Document 1, an image to be stored as a history is reduced, or an image that has been stored for a certain period has been deleted, thereby saving a storage area for storing the image. I am trying.

Japanese Patent Laid-Open No. 6-270477 (page 3, FIG. 3)

  By the way, usually, in an office, the frequency of printing a plurality of copies of the same document is very high. Taking conference materials as an example, it is common to print as many materials as are available to all attendees. However, Patent Document 1 does not assume a scene in which a plurality of copies of the same document are printed. Therefore, even when the same document is printed in a plurality of copies, the image of the document is left as a history for each printing of each copy. That is, Patent Document 1 can reduce the storage area for each image stored as a history by reducing the storage area. It did not provide usage.

The present invention has been made in order to solve the technical problems as described above, and its purpose is to efficiently use a storage area for storing images as a history in a case where a plurality of copies of the same document are often printed. Is to make it available.
Another object of the present invention is to prevent images of the same document from being stored redundantly as histories.

  For this purpose, in the present invention, images of the same document are not redundantly registered regardless of the printing format. In other words, the image storage apparatus of the present invention stores a print image of a document printed in the past, and stores a print image in any print format of the specific document when the specific document is printed. A determination unit that determines whether or not a specific document has been registered; and when the determination unit determines that the print image of the specific document has not been registered in the storage unit, the data is generated when the specific document is printed Registration means for registering the new printed image in the storage means. With such a configuration, a storage area for storing history images can be saved, and more history images can be stored.

  Here, whether or not the print image of the document has been registered is determined by storing image data together with print data (for example, data for instructing printing described in a page description language), and based on this print data. Can also be done. In that case, in the image storage device of the present invention, in the above configuration, the storage unit stores the print image of the document printed in the past together with the print data instructed to print the document, and the determination unit specifies the storage unit. Determining whether a print image in any print format of the specific document has been registered in the storage unit based on a portion of the print data stored together with the print image of the document that does not affect the print format; That's it.

  In addition, when the image of the same document has already been registered, several variations are conceivable as the processing of the registration means. First, a new print image is not registered in the storage means. Second, if the data size of the new print image is smaller than the data size of the registered print image, the new print image is registered in the storage means instead of the registered print image. Third, if the new print image has higher image quality than the registered print image, the new print image is registered in the storage means instead of the registered print image.

  Furthermore, the present invention can also be understood as such an image storage method. In this case, the image storage method of the present invention includes a step of printing a specific document, and a storage device that stores a print image of a document printed in the past. A step of determining whether or not the print image of the specific document has been registered, and if it is determined that the print image of the specific document has not been registered, a new print image generated at the time of printing the specific document is stored in the storage device Including the step of registering.

  On the other hand, the present invention can also be understood as a program for causing a computer to execute image processing. In this case, when the specific document is printed on the computer, the program of the present invention prints the specific document in any print format in the storage device storing the print image of the document printed in the past. A function that determines whether an image has been registered, and if it is determined that the print image of the specific document has not been registered, stores a new print image generated when printing the specific document This is for realizing the function to be registered in the apparatus.

  According to the present invention, it is possible to efficiently use a storage area for storing an image as a history in a scene where a plurality of copies of the same document are often printed.

The best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows the configuration of a computer system to which this embodiment is applied.
As shown in the figure, this computer system includes a printing apparatus 500 and a host computer 510. The host computer 510 is exemplified by a PC, but may be any computer as long as it can transmit a print instruction to the printing apparatus 500. The host computer 510 operates its own printer driver to generate data described in PDL (Page Description Language) (hereinafter referred to as “PDL data”), and prints it to the printing apparatus 500 together with a print instruction. And send it out. On the other hand, the printing apparatus 500 is connected to the host computer 510 via a network, and receives a print instruction transmitted from the host computer 510 via the network.

Here, the internal configuration of the printing apparatus 500 will be described in detail.
As illustrated, the printing apparatus 500 includes a PDL data input unit 501, a PDL data storage unit 502, a PDL data conversion unit 503, an image data storage unit 504, a print control unit 505, a print engine 506, and a history. An image search unit 507, a history image registration unit 508, and a history image information storage unit 509 are included.

The PDL data input unit 501 receives PDL data from the host computer 510 and stores it in the PDL data storage unit 502.
The PDL data conversion unit 503 converts the PDL data stored in the PDL data storage unit 502 into raster format image data that can be printed by the print engine 506 described later, and stores the image data in the image data storage unit 504.
The print control unit 505 transmits the image data stored in the image data storage unit 504 to the print engine 506. At that time, the print control unit 505 performs color conversion processing for converting image data into a color suitable for the print engine 506, halftone processing for converting image data expressed in multiple values into binary image data, and the like. Execute.
The print engine 506 prints an image on a medium such as paper based on the transmitted image data. The print engine 506 is exemplified by a print engine using an electrophotographic method, but may be a print engine adopting any other method.

The history image information storage unit 509 is a storage unit that stores history image information related to an image in which a document is stored as a history (hereinafter referred to as “history image”). The history image information will be described later.
The history image search unit 507 searches the image data stored in the history image information storage unit 509 using the PDL data stored in the PDL data storage unit 502 as a key. Then, the search result is notified to the history image registration unit 508. Here, since the search result is a determination result of whether or not the search target image is registered in the history image information storage unit 509, the history image search unit 507 determines whether the image of the document to be printed has been registered. It can also be grasped as a determination means for determining. The operation of the history image search unit 507 will be described later.
The history image registration unit 508 is a registration unit that registers the image data that has been printed and stored in the image data storage unit 504 in the history image information storage unit 509 in accordance with the search result by the history image search unit 507. At this time, since the PDL data before conversion is transferred from the history image search unit 507, the image data is registered together with the PDL data.

  These functions are realized by cooperation between software and hardware resources. In other words, the history image search unit 507 and the history image registration unit 508 are realized by a CPU (not shown) of the printing apparatus 500 reading a program for realizing these functions from an external storage device such as a hard disk into the main memory. .

Here, the history image information stored in the history image information storage unit 509 will be described.
FIG. 2 is a diagram showing a history image management table 701 for managing history image information. As shown in the figure, the history image management table 701 associates PDL data, image data, accompanying information, and PDL data size.
Among these, the PDL data is PDL data received from the host computer 510 (described later with reference to FIG. 4). In the figure, PDL data is expressed as PDL # 1, PDL # 2,..., But actually, the received PDL data may be stored as it is.
The image data is a print image generated according to the PDL data. In the figure, the image data is expressed as IMG # 1, IMG # 2,..., But the image data is stored in a predetermined storage area, and the pointer to the storage area is managed by the history image management table 701. It may be.

  Further, the accompanying information is information for making the image data meaningful as a log. In the figure, the user name and date are illustrated. The user name is the name of the user who printed the image, and the date is the date when the image was printed. In addition, a plurality of combinations of user names and dates can be stored for one image data. This is to cope with a case where a plurality of users print the same document or a case where the same user prints a plurality of copies of the same document. By holding such information as a history, it becomes possible to track who printed what document and when. As the accompanying information, for example, a plurality of sets of user names and dates are registered, so only the accompanying information is stored as a separate table in a predetermined storage area, and a pointer to the storage area is stored. Are preferably managed by the history image management table 701. The accompanying information is not limited to the user name and date, and any other information may be left according to the characteristics of tracking using a log.

  The PDL data size is a key item when searching for PDL data. In the figure, the PDL data size is expressed as PDL_SIZE # 1, PDL_SIZE # 2,..., But actually, it is the number of bytes of PDL data, the number of instructions, and the like. In this embodiment, since the same document history is not registered redundantly, the same PDL data is not registered redundantly, but the same PDL data size is registered redundantly. possible. This is because although the contents of PDL data are different, it is normal that the sizes are the same.

Next, the operation of the present embodiment will be described.
In the present embodiment, when a document is printed, if the print image of the document is not saved as a history, the print image is newly saved. At this time, in this embodiment, a history including a print image when the document is printed in a different print format is searched, and a new history is registered only when such a history is not saved. Yes.
Here, N-up designation is considered as an example of the print format. In this case, in this embodiment, when a certain document is printed with “No N-up designation”, not only the print image when the document is printed with the same “N-up designation” but also other N-up designation. A search is performed including a print image when printing is performed with a certain “2 up”, “4 up”, etc., and if neither of these is saved, the current print image is newly saved.

First, an example of an image to be handled in the present embodiment when N-up designation is considered as a print format and PDL data corresponding to this will be described.
FIG. 3 shows an example of an image printed in the present embodiment or stored as a history. Here, an image consisting of two pages is shown. Among these, FIG. 3A shows images 101 and 102 generated with “no N-up designation”. On the other hand, FIG. 3B shows an image 201 generated by designating “2 up”. Here, 2-up is a function for arranging images for two pages on one sheet. In general, the function of arranging N pages of images on one sheet is called an N-up function.

FIG. 4 shows PDL data corresponding to the image shown in FIG.
Among these, FIG. 4A shows the PDL data 301 sent from the host computer 510 when the image of FIG. 3A is printed.
More specifically, the PDL data 301 starts with a job start command and ends with a job end command. Between the job start command and the job end command, there is a drawing command group describing a page. Note that since the PDL data 301 is PDL data of a document composed of two pages, data for two pages is included.
The data for each page starts with a page start command and ends with a page output command. A command between these commands is a command for drawing a page. In the PDL data 301, the first page includes three character string drawing commands and one image drawing command. Similarly to the first page, the second page also includes three character string drawing commands and one image drawing command.

  In addition, between the job start instruction and the first page start instruction, an instruction (hereinafter referred to as a “job setting instruction”) for making a common setting for each page is described. One of the job setting instructions is an N-up designation instruction. In the PDL data 301, “No N-up designation” is described as this command. Therefore, when an image is printed based on the PDL data 301, each page of the document is printed on one sheet as shown in FIG. In the present embodiment, only the N-up designation command is assumed as the job setting command. The data size of the N-up designation command is a fixed length size, that is, the same size regardless of the designated content. Accordingly, the sizes of two PDL data in which only the parameters in the N-up designation instruction are different and all other instructions are the same are the same.

On the other hand, FIG. 4B shows PDL data 401 sent from the host computer 510 when the image of FIG. 3B is printed. In this way, unlike the PDL data 301, the PDL data 401 for printing a 2-up image describes “2-up” as an N-up designation command. However, instructions other than the N-up designation instruction are the same as the PDL data 301.
Here, for the sake of simplicity, the N-up designation command will be described without omission even in the case of “no N-up designation”. In other words, if an N-up designation instruction is described in a certain line in a certain PDL data, it is assumed that an N-up designation instruction is described in the same line in another PDL data.

Hereinafter, operations of the history image search unit 507 and the history image registration unit 508 will be described in detail.
FIG. 5 is a flowchart illustrating an operation example of the history image search unit 507.
When the PDL data conversion unit 503 generates image data and the print control unit 505 outputs the image data to the print engine 506, for example, whether the history image has been registered from the print control unit 505 to the history image search unit 507 is determined. A request is issued. Thereby, the history image search unit 507 starts the operation shown in FIG.
That is, the history image search unit 507 refers to the PDL data storage unit 502, and generates PDL data (hereinafter, “new PDL data”) from which newly generated image data (hereinafter, “new image data”) is based. ) Is acquired (step 602). Then, the history image information stored in the history image information storage unit 509 is searched using the size of the new PDL data as a key (step 603). Specifically, as shown in FIG. 2, since the history image management table 701 manages the PDL data size as a key item, the PDL data size acquired in step 602 from the entries in the history image management table 701. An entry including the same PDL data size is retrieved.

Next, the history image search unit 507 determines whether there are entries having the same PDL data size (step 604). As a result, if there is no entry having the same PDL data size, it is determined that the images are different (the same image data as the new image data is not registered) (step 605), and the process ends.
On the other hand, if there is an entry having the same PDL data size, one instruction (one line of the PDL data in FIG. 4) is read from the new PDL data (step 607). Then, it is determined whether this reading has been successful, that is, whether an EOF (End Of File) of PDL data has not been read (step 608). If it is determined that the reading is successful, the read instruction is stored as “instruction 1” in a memory (not shown) (step 609).

  In addition, the history image search unit 507 generates PDL data (hereinafter referred to as “registered PDL data”) from which image data (hereinafter referred to as “registered image data”) in entries having the same PDL data size in the history image management table 701 is stored. 1 instruction (one line of the PDL data in FIG. 4) is read (step 610). Then, it is determined whether this reading has succeeded, that is, whether the EOF of the PDL data has not been read (step 611). Here, if it is determined that the reading is successful, the read instruction is stored in a memory (not shown) as “instruction 2” (step 612). If it is determined in step 611 that reading has not succeeded, error processing is performed. The case where the EOF is read in step 611 is a case where the data size of the new PDL data is larger than that of the registered PDL data. However, in step 604, the data sizes of the registered PDL data and the new PDL data are determined to be the same. Therefore, if the normal operation is performed, it is impossible to read the EOF here.

Thereafter, the history image search unit 507 determines whether or not the instruction 1 is an N-up designation instruction (step 613). As a result, when it is determined that the instruction 1 is not an N-up designation instruction, it is determined whether the instruction 1 and the instruction 2 are the same (step 614). Here, if it is determined that the instruction 1 and the instruction 2 are the same, the process proceeds to step 607 and the next instruction is checked. If it is determined that the command 1 and the command 2 are not the same, it is determined that the new image data and the registered image data are different images (image data based on different documents) (step 605).
On the other hand, if it is determined in step 613 that the instruction 1 is an N-up designation instruction, the process proceeds directly to step 607 without performing step 614, and the next instruction is checked. In the case of this embodiment, only the N-up designation command is a command that affects the print format of the image, not a command that affects the content of the image. Therefore, the new image data and the registered image data are the same. This is because it is an instruction that is unnecessary for determining whether or not there is (image data based on the same document).

  If the reading is not successful in step 608, that is, if the EOF is read from the new PDL data, one command (one line of the PDL data in FIG. 4) is read from the registered PDL data (step 617). Then, it is determined whether this reading has succeeded, that is, whether the EOF of PDL data has not been read (step 618). If it is determined that the reading has not been successful, it is determined that the new image data and the registered image data are the same image (image data based on the same document) (step 619). If it is determined in step 618 that the reading is successful, error processing is performed. The case where the EOF is not read in step 618 is a case where the data size of the registered PDL data is larger than that of the new PDL data. However, in step 604, the data size of the registered PDL data and the new PDL data is determined to be the same. This is because the EOF should be read here if the operation is normal.

The processing of the history image search unit 507 has been described above. In this embodiment, the same processing is performed for all entries having the same PDL data size in the history image management table 701. If it is determined in step 605 that the image is different from the process focused on a certain entry, the same process is performed focusing on the next entry. The same processing is repeated until it is determined in step 619 that the images are the same or there is no entry having the same PDL data size.
As a result of such processing, it is finally determined whether an image having the same content as the new image data (an image generated from the same document) exists in the history image information storage unit 509, and the determination result is registered as a history image registration. Passed to section 508. At that time, new PDL data is also passed from the history image search unit 507 to the history image registration unit 508.

FIG. 6 is a flowchart showing an operation example of the history image registration unit 508.
First, the history image registration unit 508 evaluates the determination result passed from the history image search unit 507 (step 802).
Here, when the determination result is “the same image exists”, new image data is extracted from the image data storage unit 504, and registered image data is extracted from the history image information storage unit 509, and the data sizes of these image data are compared. (Step 803). Then, it is determined whether or not the data size of the new image data is smaller than the data size of the registered image data (step 805).

As a result, if it is determined that the data size of the new image data is larger, the process proceeds to step 808 without replacing the image data or the like. If it is determined that the data size of the new image data is smaller, In order to effectively use the storage area for storing the image data, a process for replacing the image data and the like is performed. That is, first, the history image registration unit 508 replaces the registered PDL data in the target entry of the history image management table 701 with new PDL data (step 806). Next, the registered image data in the entry is replaced with new image data (step 807).
Then, in step 805, even when it is determined that the data size of the new image data is larger than the data size of the registered image data, or when it is determined that the data size is smaller, the associated entry is registered in association with the target entry. (Step 808). For example, in FIG. 2, a combination of the user name and date related to the current printing is added to a plurality of combinations of the user name and date associated with each entry.

  If the determination result is “no identical image” in step 802, an entry in which the data size of the new PDL data is set to the PDL data size is added to the history image management table 701 (step 809). Next, new PDL data is registered in the newly added entry (step 810). Then, the new image data is extracted from the image data storage unit 504 and registered in the same entry (step 811). In this case, new image data may be stored in a predetermined storage area, and a pointer to the storage area may be stored in the entry. Then, the history image registration unit 508 registers a set of user name and date in the same entry (step 812). Also in this case, the user name and date pair may be stored in a predetermined storage area, and a pointer to the storage area may be stored in the entry.

This is the end of the description of the present embodiment.
By the way, in the present embodiment, when the image data generated from the same document has already been registered, the size relationship between these data sizes is determined by directly comparing the image data, and the image with the smaller data size is determined. The data is preferentially left in the history. However, the determination method of the size relationship of the data size of the image data is not limited to this. That is, when only the contents of the N-up designation are different between the new PDL data and the registered PDL data, the magnitude relationship between the image data generated by these PDL data can be determined by comparing the N-up designation commands. It is possible to determine. For example, if one PDL data is described as “N-up not specified” and the other PDL data is described as “2 up”, the latter PDL data is used based on the difference in these descriptions. It can be determined that the generated image data has a smaller data size.

Here, the operations of the history image search unit 507 and the history image registration unit 508 in an embodiment adopting such a determination method (hereinafter referred to as “modified example”) will be described.
FIG. 7 is a flowchart illustrating an operation example of the history image search unit 507 in the present modification.
Since this flowchart is substantially the same as the flowchart shown in FIG. 5, steps that perform the same processes as those in FIG. 5 are denoted by the same reference numerals. On the other hand, the only difference from FIG. 5 is processing when it is determined in step 613 that instruction 1 is an N-up designation instruction. In FIG. 5, since only the N-up designation command is excluded from the commands that match between the new PDL data and the registered PDL data, if the determination in step 613 is “Yes”, the process proceeds to step 607 without doing anything. I did it. On the other hand, in FIG. 7, when the determination in step 613 is “Yes”, it is first determined whether or not the instruction 2 is also an N-up designation instruction (step 615). As a result, if it is determined that the instruction 2 is also an N-up designation instruction, the contents of the instruction 1 and the instruction 2 are stored in a memory (not shown) (step 616). If it is not determined in step 615 that instruction 2 is an N-up designation instruction, error processing is performed. In the present embodiment, as described above, it is assumed that the N-up designation command is described in the corresponding lines of the new PDL data and the registered PDL data, whether or not N-up is designated. Yes. Therefore, if the normal operation is performed, the N-up designation command cannot be detected from only one side.

Thereafter, the history image registration unit 508 operates.
The operation of the history image registration unit 508 in this modification is the same as that shown in FIG.
In FIG. 6, in step 805, the new image data and the registered image data are directly compared to determine the size relationship between the data sizes. However, in this modification, the size relationship between the new image data and the registered image data is determined by referring to the contents of the instruction 1 and the instruction 2 stored in step 616 of FIG.
This is the end of the description of this modification.

  In the present embodiment, more images are stored as history, so images with N-up designation (images with a small data size) are given priority over images without N-up designation (images with a large data size). To save. However, depending on the use of the history image, it may be considered that the image quality of the history image is more important than saving the storage area. In such a case, an image without N-up designation (high-quality image) may be preferentially stored over an image with N-up designation (low-quality image). Alternatively, other conditions other than this may be set, and when the conditions are satisfied, the new image data may be stored instead of the registered image data.

  Furthermore, in the present embodiment, the N-up designation is taken up as an example of a parameter that affects the print format, but the present invention is not necessarily limited to this. For example, the present embodiment can also be applied to color mode designation for designating color output or monochrome output, pixel depth designation, and the like.

  Furthermore, in this embodiment, PDL data is stored with respect to image data, including a portion that affects the print format and a portion that does not affect the print format. However, it is also possible to separate the PDL data into a part that affects the printing format and a part that does not affect the printing format, and register only the latter part in association with the image data or use it for the search. Specifically, as shown in FIG. 8, in the case where the PDL data is composed of an output control data portion that affects the print format and a basic data portion that does not affect the print format, the image data and the basic data of the PDL data Are stored in the history image information storage unit 509. That is, when registering PDL data # 1 with “N-up not specified” or when registering PDL data # 2 with “2-up” specified, only the basic data portion that does not affect the print format is registered. is there. As a result, when there is a new print request, it is possible to perform a search focusing on only the basic data portion of the PDL data, and as a result, the determination process as in step 613 in FIG. The search process can be made more efficient.

  In the present exemplary embodiment, the history image search unit 507, the history image registration unit 508, and the history image information storage unit 509 are configured to exist in the printing apparatus 500. However, an external device connected via a network is used. The image history server (image log server) may be provided.

  As described above, in the present embodiment, it is determined whether or not a history image for the same document has already been registered, and only when it has not been registered, it is newly registered. As a result, it is possible to effectively use the storage area for storing the history images, and as a result, it is possible to store more image histories.

It is the figure which showed the structure of the computer system with which embodiment of this invention is applied. It is the figure which showed the structural example of the log | history image management table in embodiment of this invention. It is the figure which showed the example of the image data produced | generated by embodiment of this invention. It is the figure which showed the example of the PDL data used as the origin of the image data produced | generated by embodiment of this invention. It is the flowchart which showed the operation example of the log | history image search part in embodiment of this invention. It is the flowchart which showed the operation example of the log | history image registration part in embodiment of this invention. It is the flowchart which showed another example of operation | movement of the log | history image search part in embodiment of this invention. It is the figure which showed another registration method of the PDL data in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 500 ... Printing apparatus, 501 ... PDL data input part, 502 ... PDL data storage part, 503 ... PDL data conversion part, 504 ... Image data storage part, 505 ... Print control part, 506 ... Print engine, 507 ... History image search part 508: History image registration unit 509: History image information storage unit

Claims (13)

Storage means for storing print images of documents printed in the past;
A determination unit that determines whether a print image in any print format of the specific document has been registered in the storage unit when the specific document is printed;
Registration for registering a new print image generated at the time of printing the specific document in the storage unit when the determination unit determines that the print image of the specific document has not been registered in the storage unit And an image storage device. The storage means stores a print image of a document printed in the past together with print data instructed to print the document,
The determination unit stores the print image in any print format of the specific document based on a portion that does not affect the print format of the print data stored together with the print image of the specific document in the storage unit. 2. The image storage apparatus according to claim 1, wherein it is determined whether or not the information has been registered in the means.   The registration unit does not register the new print image in the storage unit when the determination unit determines that the print image of the specific document has been registered in the storage unit. Item 2. The image storage device according to Item 1.   If the determination unit determines that the print image of the specific document has been registered in the storage unit, the registration unit registers the new print image if a predetermined condition is satisfied. The image storage apparatus according to claim 1, wherein the image storage device is registered in the storage unit instead of the already-printed image.   The image storage device according to claim 4, wherein the predetermined condition is a condition that a data size of the new print image is smaller than a data size of the registered print image. The storage means stores a print image of a document printed in the past together with print data instructed to print the document,
The registering unit affects a print format of print data instructing printing of the specific document and a print format of print data stored in the storage unit together with a print image of the specific document. 6. The image storage device according to claim 5, wherein the data size of the new print image is compared with the data size of the registered print image based on the portion.   5. The image storage device according to claim 4, wherein the predetermined condition is a condition that the new print image has higher image quality than the registered print image. Printing a specific document;
Determining whether a print image in any print format of the specific document has been registered in a storage device storing a print image of a document printed in the past;
Registering a new print image generated at the time of printing the specific document in the storage device when it is determined that the print image of the specific document has not been registered. Image storage method.   In the registering step, when it is determined that the print image of the specific document has been registered, if the data size of the new print image is smaller than the data size of the registered print image, the new document The image storage method according to claim 8, wherein a simple print image is registered in the storage device instead of the registered print image.   In the registering step, when it is determined that the print image of the specific document has been registered, if the new print image has a higher image quality than the registered print image, the new print image The image storage method according to claim 8, wherein the image is registered in the storage device instead of the registered print image. On the computer,
A function for determining whether or not a print image in any print format of the specific document has been registered in a storage device storing a print image of the document printed in the past when the specific document is printed. When,
A program for realizing a function of registering a new print image generated at the time of printing the specific document in the storage device when it is determined that the print image of the specific document is not registered.   In the registering function, when it is determined that the print image of the specific document has been registered, if the data size of the new print image is smaller than the data size of the registered print image, the new document The program according to claim 11, wherein a simple print image is registered in the storage device in place of the registered print image.   In the registering function, if it is determined that the print image of the specific document has been registered, and the new print image has a higher image quality than the registered print image, the new print image 12. The program according to claim 11, wherein the program is registered in the storage device in place of the registered print image.

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