JP2004312242A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of efficiently utilizing a memory for storing image data. <P>SOLUTION: The image forming apparatus for storing received image data, applying image processing to the image data as required and thereafter printing out the processed data on a transfer member, includes: a memory used for storing the received image data and for the image processing required at print; and a control means for controlling the storage of the image data to the memory at the reception and the image processing of the image data at print, and the control means is characterized in to reserve a prescribed capacity for the image processing applied to the image data to be printed by revising a threshold value for discrimination of limit of reading due to deficient memory capacity when storing the received image data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus that stores input image data, prints the image on a transfer material after performing image processing as necessary, and particularly relates to storage of input image data or image processing required for printing. The present invention relates to an improvement in the allocation of storage capacity of a used memory.
[0002]
[Prior art]
In recent years, in an image forming apparatus such as a digital copying machine, an image of a plurality of originals is sequentially read by an automatic original reading apparatus, the read original images are sequentially converted into digital image data, and the converted image data is stored in a memory. Remember.
[0003]
Then, the image data stored in the memory is read out and the image of the document is printed on the transfer material. For this reason, the image of the document can be read only once, and the required number of copies can be formed from the image data stored in the memory. Such a technique is called an electronic RDH (recirculate document handler).
[0004]
In the electronic RDH, image data is stored in a memory, but image data is compressed and stored in the memory for the purpose of reducing the storage capacity of the memory. When forming an image, the compressed image data is read from the memory and decompressed to become the original image data.
[0005]
In the electronic RDH, since the image of the document is converted into image data of a digital signal, it is possible to edit the image of the image data by image processing and print it on a transfer material. The image editing includes, for example, rotation of an image, superposition of two images, arrangement of an image at an arbitrary position, writing of characters and graphics at an arbitrary position, and the like.
[0006]
However, image editing cannot be performed while image data is compressed. Therefore, in the conventional image forming apparatus, the storage capacity required for image editing is always secured in the memory, the compressed image data is decompressed (bitmap expanded), and then the image data is stored in the secured memory. Was editing the image from.
[0007]
However, the storage capacity secured in the memory for image editing significantly varies depending on the image content of the document, image forming conditions such as resolution and the number of gradations to be printed on the transfer material. For this reason, in the conventional image forming apparatus, it is necessary to always secure a storage capacity of several megabytes to several tens of megabytes in the memory based on the image forming condition requiring the most storage capacity.
[0008]
In recent image forming apparatuses, input image data is handled in job units, the next job can be accepted during printing, and image data of a plurality of jobs can be stored in the memory. Have been. In such an image forming apparatus, a memory for image editing is shared with storage of compressed image data. For this reason, storage of the compressed image data occupies most of the memory, and there is a problem that the capacity for image editing becomes insufficient and image formation is interrupted.
[0009]
In order to prevent the image formation from being interrupted due to the shortage of the capacity for image editing as described above, in the technology described in Patent Document 1 below, the capacity for image editing is secured in the memory in advance.
[0010]
[Patent Document 1]
JP-A-2002-176543 (Page 1, FIG. 1)
[0011]
[Problems to be solved by the invention]
Note that the memory for image editing is shared with storage of compressed image data. That is, in addition to the image editing, the input compressed image data and the image data being printed share the same memory.
[0012]
Therefore, if the compressed image data that has been read and stored exists in the memory and the image data that is being printed exists in the memory, the technique disclosed in Patent Document 1 secures a capacity for image editing. You may fall into an impossible state. That is, the capacity for image editing cannot be secured, and the operation of the image forming apparatus is interrupted or stopped due to an error.
[0013]
Even if the interruption or stop is not performed as an error, a useless capacity is secured in the memory until the image editing is actually started. As a result, another problem that storage of new compressed image data is limited occurs.
[0014]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of solving the above-mentioned problems and efficiently performing a printing operation by efficiently using a memory.
[0015]
[Means for Solving the Problems]
The above-mentioned problems can be solved by the following means for solving the problems.
[0016]
(1) An invention according to claim 1 is an image forming apparatus that stores input image data, prints the image data on a transfer material after performing image processing as necessary, and stores the input image data. A memory used for image processing required at the time of printing, and control means for controlling storage of image data in the memory at the time of input and image processing of image data at the time of printing, the control means, By changing the threshold value for determining the read restriction due to lack of memory when storing image data at the time of input, it is possible to reserve a predetermined capacity for image processing for image data to be printed next. This is a characteristic image forming apparatus.
[0017]
According to the present invention, when input image data is stored and printed on a transfer material after image processing is performed as necessary, a memory is used for storing the input image data and performing image processing at the time of printing. By changing the threshold value for determining the read restriction due to lack of memory when storing the image data at the time, a predetermined capacity for image processing for the image data to be printed next is reserved.
[0018]
Here, the threshold value for determining the read restriction due to lack of memory when storing the image data at the time of input means the upper limit of the storage when the input image data is stored in the memory. I have.
[0019]
Thus, in addition to the storage for editing the image to be printed, the storage of the input compressed image data and the storage of the image data being printed share the same memory. Even if the stored compressed image data exists in the memory and the image data being printed already exists in the memory, the capacity for image editing of the image to be printed cannot be secured. As a result, it is possible to avoid a situation in which the image forming operation is interrupted or stopped due to an error.
[0020]
Further, it is possible to avoid the problem of securing a useless capacity in the memory until the image editing for the image to be printed is actually started. As a result, it is possible to avoid the problem that the storage of new compressed image data is limited.
[0021]
(2) The invention according to claim 2 is characterized in that the control means checks whether or not image editing is performed at the time of printing, and reserves a predetermined capacity of the memory when image editing is performed. An image forming apparatus according to claim 1.
[0022]
According to the present invention, in the above (1), it is checked whether or not image editing is performed at the time of printing. When image editing is performed, a memory is used for storing input image data and performing image processing at the time of printing. By changing the threshold value for determining the read restriction due to lack of memory when storing the image data at the time, a predetermined capacity for image processing for the image data to be printed next is reserved.
[0023]
By doing as described above, the memory can be efficiently used as needed, and the printing operation can be smoothly performed according to various states such as the presence or absence of image editing.
[0024]
(3) The invention according to claim 3 is characterized in that the control means determines the storage capacity reserved in the memory by referring to the number of gradations and the print size when performing image formation. An image forming apparatus according to claim 1 or 2.
[0025]
In the present invention, in the above (1) or (2), the storage capacity reserved in the memory is determined by referring to the number of gradations and the print size when performing image formation, and the image processing for the image data to be printed next is performed. Reserve a predetermined capacity for
[0026]
By doing as described above, the memory can be efficiently used as needed, and the printing operation can be smoothly performed according to various states such as the presence or absence of image editing.
[0027]
(4) According to the fourth aspect of the invention, it is possible to handle input image data in units of jobs, accept a next job during printing, and store image data of a plurality of jobs in the memory. An image forming apparatus configured so as to be capable of changing a print output order of a job, wherein the control unit relates to a job of image data for which a storage capacity is reserved in the memory. 4. The image forming apparatus according to claim 1, wherein control is performed to prohibit a change in the order of print output from another job.
[0028]
According to the present invention, in (1) or (2), when a predetermined capacity for image processing for image data to be printed next is reserved, a job of image data for which a storage capacity is reserved in a memory is used. The print output order is prohibited from being changed with the other jobs.
[0029]
In the manner described above, the reservation of the predetermined capacity can be effectively handled, and the memory can be efficiently used as necessary. The printing operation can be performed smoothly.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of an image forming apparatus to which an embodiment of the present invention is applied will be described below with reference to the drawings.
[0031]
<Mechanical configuration>
First, referring to FIG. 2, the mechanical configuration of the image forming apparatus according to the embodiment of the present invention will be described first. Although FIG. 2 illustrates an example of monochrome image formation, the embodiment of the present invention can be applied to a color image forming apparatus. Further, the embodiment of the present invention can be applied to an image forming apparatus using an intermediate transfer member.
[0032]
FIG. 2 is a schematic diagram of the image forming apparatus A of the present invention. The image forming apparatus A includes an automatic document feeder DF, a scanner B, and a rotating image carrier 1, which are openably supported at the upper portion thereof, and a charging unit 2, a writing unit 3, a developing unit 4, a transfer unit 5, It has a static elimination unit 6A, a separation unit 6B, a fixing unit 7, a paper feeding unit 9, an electric circuit storage unit 10, an operation input unit H, and the like. Hereinafter, each means will be described.
[0033]
The automatic document feeder DF has a one-sided original reading function and a two-sided original reading function based on the original moving type reading method provided on the upper part of the image forming apparatus A, and conveys the placed original to feed the original of the scanner apparatus B. It passes through the reading position.
[0034]
The scanner device B converts the optical information of the image of the document conveyed to the document reading position into an electric signal.
[0035]
The image carrier 1 includes, for example, a cylindrical base formed of a transparent member of a transparent acrylic resin provided inside, and a transparent conductive layer or a photosensitive layer such as an organic photosensitive layer formed on the outer periphery of the base. The motor rotates in the direction shown by the arrow.
[0036]
The charging unit 2 is disposed around the image carrier 1 and, for example, performs a corona discharge by a scorotron-type wire discharge electrode to apply a predetermined potential to the image carrier 1 before an electrostatic latent image is formed. Charge.
[0037]
The writing unit 3 is an exposure unit that exposes the image carrier 1 by scanning a light beam from a laser light source by deflection caused by rotation of a polygon mirror.
[0038]
The developing means 4 is provided with a developing sleeve provided with magnetic poles at a predetermined gap, for example, at an interval of 100 μm to 500 μm, from the image carrier 1 by an abutting roller (not shown), and makes the stored developer adhere to the developing sleeve The developer attached by the rotation is supplied to the image carrier 1. The supplied developer visualizes an electrostatic latent image on the image carrier 1 as a toner image by a developing magnetic field formed between the developing sleeve and the image carrier 1.
[0039]
The transfer unit 5 is provided to face the image carrier 1, and the toner image formed on the image carrier 1 is fed from a paper feed unit 9 by a transfer electric field formed between the transfer unit 5 and the image carrier 1. Transfer onto a transfer material.
[0040]
The charge removing unit 6 </ b> A is provided to face the image carrier 1, and erases the charge of the transfer material generated in the transfer electric field by the separation electric field formed between the image carrier 1 and the image carrier 1. In addition, the separating unit 6B separates the transfer material that is in close contact with the image carrier 1 by the transfer unit 5.
[0041]
The fixing unit 7 includes a pair of pressure rollers provided with a heating source, and presses and heats the transfer material on which the toner image has been transferred to fix the toner image on the transfer material.
[0042]
The paper feeding unit 9 stores a transfer material on which a toner image is formed, and feeds the transfer material toward the image carrier 1 every time image formation is requested. Here, the transfer material accommodated in the paper feeding means 9 is a material in which characters and figures are reproduced in a tangible manner, and specifically, a sheet of paper, cloth or the like cut into a predetermined size, This is a roll of paper or cloth before being cut.
[0043]
The operation input unit H includes a liquid crystal panel, operation keys, and the like, and displays a message from the apparatus to the operator, and inputs image forming conditions desired by the operator from the liquid crystal panel and the operation keys.
[0044]
The image forming conditions include selection of whether or not image data is to be edited and printed by the electronic RDH, conditions of image editing when image editing is selected, resolution for printing, number of gradations, Output conditions such as density, size and number of transfer materials, selection of single-sided or double-sided printing, and the like. The operator sets the image forming conditions before forming the image.
Operation input means
After inputting from H, image formation is started.
[0045]
The electric circuit storage unit 10 includes various control boards such as control means for controlling the operation of the image forming apparatus A, a memory for storing image data, and various processing means such as an image processing unit for image processing image data. It is stored.
[0046]
<Electrical configuration>
Next, an electrical configuration including a control unit that controls the operation of each unit of the image forming apparatus A will be described. FIG. 1 is a block diagram illustrating an electrical configuration of the image forming apparatus A.
[0047]
The control means 20 includes a CPU (Central Processing Unit), a memory for control processing, a ROM (Read Only Memory) for storing programs, and the like. The image forming apparatus is based on image forming conditions input to the operation input means H. An image is formed on the transfer material by controlling each part of A.
[0048]
The image processing means 21 converts an analog electric signal of the image of the document read by the scanner B into image data of a digital signal by image processing. Further, based on the input editing conditions, the image data is developed in the memory 24 to perform various types of image editing. Note that the image editing in the image processing unit 21 includes image rotation, superposition of a plurality of images, arrangement at an arbitrary position of an image, writing of characters and graphics in an image at an arbitrary position, and the like.
[0049]
The compression unit 22 generates compressed image data by compressing the data capacity of the image data using a dedicated IC employing an adaptive predictive coding method, for example, an AHA algorithm or the like.
[0050]
After the image data of the document read by the scanner device B and image data input from outside (input image data) are converted into compressed image data, the compressed image data is stored in the memory 24. The storage capacity of the memory 24 is saved.
[0051]
The decompression means 23 decompresses the data capacity of the image data compressed by the above-described compression means 22 and returns it to the image data before compression.
[0052]
The memory 24 is a storage unit composed of a rewritable DRAM (a random write / read memory that requires a storage holding operation) and the like. The expanded image data is stored. The memory 24 is also used as a work area when editing an image.
[0053]
The reading control unit 25 controls the scanner device B and the automatic document feeder DF to convey the document placed on the document table of the scanner device B, and performs control to read the image of the document at a predetermined timing. .
[0054]
The writing control unit 26 controls the exposure unit of the writing unit 3 based on the image data to expose the image carrier 1 uniformly charged by the charging unit 2, and performs an exposure to the electrostatic latent image on the image carrier 1. To form
[0055]
The overall control unit 27 controls the control of each unit of the image forming apparatus A other than the control based on the image data, for example, controls the transfer control of the transfer material, the development control of the developing unit 4, the heating control of the fixing unit 7, and the like. This is performed according to the instruction of the means 20.
[0056]
Next, an image forming process of the image forming apparatus A will be described. The control unit 20 controls each unit as follows so as to satisfy the image forming conditions input to the operation input unit H, and forms an image.
[0057]
First, the reading control unit 25 converts an image of a document from optical information into an electric signal. The image processing means 21 converts the electric signal of the image of the document into image data of a digital signal by image processing. The image processing means 21 may handle not only an image of a document conveyed by the automatic document feeder DF but also an image received from outside such as a communication network.
[0058]
The converted image data is compressed by the compression means 22 and stored in the memory 24. Thereafter, the image data compressed when the image is formed on the transfer material is read from the memory 24 and decompressed by the decompression means 23. Here, when the image editing is selected from the image forming conditions input to the operation input means H, a memory capacity for editing the expanded image data is secured in the memory 24 before printing on the transfer material.
[0059]
Then, the expanded image data is expanded to the secured storage capacity of the memory 24, and image editing is performed.
[0060]
On the other hand, when the drive motor (not shown) is started, the image carrier 1 is rotated in the direction shown by the arrow, and at the same time, a predetermined potential is applied to the image carrier 1 by the corona discharge action of the charging means 2. Next, an electrostatic latent image corresponding to the image data is formed on the surface of the image carrier 1 by the writing control unit 26. The formed electrostatic latent image is developed by the developing unit 4, and a toner image is formed on the image carrier 1.
[0061]
The transfer material on which an image is formed is fed from a paper feeding unit 9 and is conveyed toward the image carrier 1. The registration roller 8A starts rotating in synchronization with the toner image formed on the image carrier 1, and conveys the transfer material to the image carrier 1. The toner image of the image carrier 1 overlaps the transfer material conveyed in synchronization with the image carrier 1, and the transfer unit 5 transfers the toner image to the transfer material. The transfer material is neutralized by the neutralizing means 6A and separated from the image carrier 1 by the separating means 6B. Thereafter, the toner is conveyed to the fixing unit 7 and the toner powder for forming the toner image is heated and pressed by the fixing unit 7 so as to be melt-fixed on the transfer material. The transfer material on which the toner image is fixed and the image is formed is discharged from the image forming apparatus A via the discharge roller 8B.
[0062]
When performing image formation on the back surface of the transfer material having the first toner image transferred on the front surface, the transfer path switching member 8C is controlled to direct the transfer material to a pair of switchback rollers 8D capable of rotating forward and reverse. Transport. The switchback roller 8D stops rotating while holding the rear end of the transfer material, and then starts rotating in the reverse direction to convey the transfer material toward the conveyance roller 8E. The transport roller 8E transports the transfer material and transports it to the registration roller 8A before starting rotation. At this time, the transfer material is sent to the registration roller 8A in a state where the transfer material is turned upside down, that is, in a state where the back surface on which the toner image is not transferred is directed to the image carrier 1 side.
[0063]
A second toner image is formed on the image carrier 1, and the registration roller 8A starts rotating in synchronization with the second toner image formed on the image carrier 1 to convey the transfer material. . The second toner image overlaps the back surface of the transfer material conveyed in synchronization with the image carrier 1, and the second toner image is transferred to the back surface of the transfer material by the urging of the transfer unit 5. Thereafter, the separation and fixing processes are performed, and the transfer material is discharged via the paper discharge roller 8B.
[0064]
<Image input processing>
Next, image input, which is a characteristic part of the embodiment of the present invention, will be described below. FIG. 3 is a flowchart relating to image input of the image forming apparatus A under the control of the control means 20.
[0065]
When inputting image data of a document read by the scanner device B or inputting image data from outside (image input), the user (operator) of the image forming apparatus inputs the image of the image forming conditions to the operation input means H. A selection as to whether or not to perform editing is input (S301).
[0066]
Even when intentional image editing is not performed (N in S301), image rotation is required due to the relationship between the direction of the input image data and the direction of the transfer material stocked in the image forming apparatus. There are cases. For example, this corresponds to a case where the input image data is A4 size, and the A4 transfer material stocked in the image forming apparatus is in the A4R direction. In such a case, it is necessary to form the image while rotating the input image data by 90 degrees. Therefore, the control unit 20 checks whether or not the image has been rotated (S302).
[0067]
When it is determined that image editing is input to the operation input unit H (Y in S301) or when the control unit 20 determines that image rotation is performed (Y in S302), the control unit 20 performs the following processing. Execute.
[0068]
That is, the control unit 20 changes the threshold value for determining the read restriction due to the lack of memory when storing the image data at the time of input (S302), so that the image processing for the image data to be printed next is performed. To reserve a given capacity. Here, the memory shortage read restriction means a read restriction due to a memory shortage.
[0069]
This reservation is merely a change of the threshold value for storing the input image data, and is different from actually exclusively securing the image data. Therefore, other data (for example, the current print processing) is already stored in the area. There is no problem even if there is expanded image data during execution of (i.e., image data of a job waiting to execute print processing).
[0070]
This is shown in FIG. FIG. 5A shows an example of a conventional basic input processing, in which input image data is accumulated in the memory 24 as compressed image data. Further, at the time of printing in FIG. 5B, image data to be printed is stored in a state where the image data is developed into a bitmap. The input compressed image data occupies most of the memory 24 (direction (1) in FIG. 5B), and the memory capacity required for printing (direction (2) in FIG. 5B). Otherwise, the printing process stops as an error.
[0071]
FIG. 6 shows a processing example described in the conventional patent document 1. When input image data is accumulated in the memory 24 as compressed image data, the capacity of the image data to be printed next is changed to another application (compression). It is exclusively reserved in advance so as not to be used for storing image data (4) (FIG. 5 (a) (3)).
[0072]
That is, even before the image editing for the image to be printed is actually started, the previously secured area is stored in another image data (for example, storage of input image data, It cannot be used for storing image data during processing (not shown). For this reason, there is a problem that a useless capacity is secured on the memory. As a result, a problem occurs that the storage of new compressed image data is limited. Further, if the memory 24 is used for storing the input image data or storing the image data which has already been subjected to the printing process, and the capacity of the image data to be printed next cannot be secured in advance, the actual situation still remains. However, the printing process stops as an error despite the unused capacity.
[0073]
FIG. 7 shows a state of memory reservation according to the embodiment of the present invention. Here, the threshold value for determining the read restriction due to the lack of memory when storing the image data at the time of input is the same as that when the input image data is stored in the memory 24 as the compressed image data as shown in FIG. If it is stored in the (6) direction, it means the upper limit of the storage. That is, when the image input is received up to the upper limit value, and the threshold value is overflown, the reading restriction due to the lack of memory occurs, and the reception of the image input is temporarily suspended under the control of the control unit 20.
[0074]
In such a case, by changing the threshold value (S302, (5) in FIG. 7A), a predetermined capacity for image processing for image data to be printed next can be appropriately reserved. . FIG. 7A shows an example in which other data and image data of another developed job that is currently executing print processing already exist in the area. This reservation is merely a change of the threshold value for storing the input image data, and is different from actually exclusively securing the image data. Therefore, there is image data for the preceding print processing. You may.
[0075]
Accordingly, in addition to the storage for editing the image to be printed, the storage of the input compressed image data and the storage of the image data being printed are already read in the case where the same memory 24 is shared. Even if the compressed image data stored in the memory exists in the memory and the image data being printed already exists in the memory, the capacity for image editing of the image to be printed cannot be secured. As a result, it is possible to avoid a situation in which the image forming operation is interrupted or stopped due to an error.
[0076]
Until the image editing for the image to be printed is actually started, the reserved area is stored in another image data (for example, image data that is being printed in advance). Since 24 can be used, it is possible to avoid the problem of securing an unnecessary capacity on the memory. As a result, it is possible to avoid the problem that the storage of new compressed image data is limited.
[0077]
In this case, the control unit 20 preferably determines the storage capacity reserved in the memory 24 by calculation with reference to the number of gradations and the print size when performing image formation. Note that the print size corresponds to the total number of pixels obtained from the size of the transfer material and the pixel density. The total number of pixels multiplied by the number of gradation bits corresponds to the storage capacity. In this way, the storage capacity to be reserved by the control means 20 is obtained.
[0078]
For example, when printing on an A4 size transfer material (297 mm in width, 210 mm in depth), a resolution of 600 / 25.4 mm, and an output condition of 1 bit of gradation, the storage capacity reserved in the memory 24 is about 4.35 megabytes. Become. That is, since the storage capacity for image editing reserved in the memory 24 is varied according to the output conditions, the memory 24 is efficiently used.
[0079]
Further, it is preferable that the control unit 20 performs control so as to prohibit the change of the print output order from another job with respect to the job of the image data for which the storage capacity has been reserved in the memory 24. Thus, it is not necessary to change the reserved storage capacity, and it is possible to smoothly execute image formation.
[0080]
Further, the control unit 20 not only prohibits the change of the print output order with respect to the job of the image data for which the storage capacity has been reserved in the memory 24, but also all the jobs existing at that time. Also, the change of the output order may be prohibited. This not only eliminates the need to change the reserved storage capacity, but also has the advantage of making job management easier.
[0081]
When a storage capacity for image editing is reserved in the memory 24, when there are a plurality of documents, the images of the documents are read one after another, converted into image data, and the converted image data is compressed to compress the compressed image data. It is generated and stored in the memory 24 one after another (S304).
[0082]
Hereinafter, the storage of the input image data as compressed image data (S304) may cause a memory overflow (the occurrence of read restriction due to insufficient memory) when the threshold is reached (Y in S305), or The process is continued until there is no more (Y in S306) (S304).
[0083]
<Print processing>
Next, image formation, which is a characteristic part of the embodiment of the present invention, will be described below. FIG. 4 is a flowchart relating to image formation of the image forming apparatus A under the control of the control means 20.
[0084]
The preparation of the writing means 3 of the image forming apparatus is completed by, for example, ending the processing of another job which is performing image formation in advance and a job waiting for image formation after the job which is performing image formation. When the writing control means 26 detects that the state has been reached, this state is notified to the control means 20. At this point, the control unit 20 instructs each unit to execute printing.
[0085]
Here, the control unit 20 checks whether it is necessary to secure a page memory in the memory 24 in the printing process (S401). That is, it is determined whether intentional image editing by an operator's instruction or image rotation based on the relationship between the direction of input image data and the direction of the transfer material is necessary.
[0086]
Then, when the intentional image editing by the operator's instruction or the image rotation due to the relationship between the direction of the input image data and the direction of the transfer material is necessary, that is, when the page memory needs to be secured (Y in S401). The control means 20 secures a page memory on the memory 24 (S402). At this time, the control means 20 may determine whether or not to perform image editing or image rotation to determine whether or not it is necessary to secure a page memory.
[0087]
The page memory is reserved to occupy the area reserved at the time of image input for actual processing.
[0088]
FIG. 7C shows a state where the control means 20 secures a page memory on the memory 24. At the time of this printing, the other jobs that have been printing earlier have been completed, and the reserved capacity is in an empty state (FIG. 7B).
[0089]
When the page memory is secured (Y in S401), the page memory is used, and when the page memory is not secured (N in S401), the printing operation is performed by the writing unit 3 without using the page memory. Is executed (S403).
[0090]
Here, the control means 20 checks whether or not it is necessary to continue to secure a page memory in the memory 24 in the subsequent processing (S404). When the page memory is not used (Y in S404), the page memory is released, and when the page memory is used (N in S404), the page memory is not released.
[0091]
Here, the control means 20 checks whether or not the printing process is completed (S406). If there is an image to be printed (N in S406), the process returns to S401 to continue the printing process.
[0092]
As described above, in the embodiment of the present invention, the image to be printed next is changed by changing the threshold value for determining the read restriction due to lack of memory when storing image data at the time of input. Reserve a predetermined capacity for image processing on the data. Thus, in addition to the storage for editing the image to be printed, the storage of the input compressed image data and the storage of the image data being printed share the same memory. Even if the stored compressed image data exists in the memory and the image data being printed already exists in the memory, the capacity for image editing of the image to be printed cannot be secured. As a result, it is possible to avoid a situation in which the image forming operation is interrupted or stopped due to an error. Further, it is possible to avoid the problem of securing a useless capacity in the memory until the image editing for the image to be printed is actually started. As a result, it is possible to avoid the problem that the storage of new compressed image data is limited.
[0093]
Further, as described above, in the embodiment of the present invention, it is determined whether or not image editing is performed at the time of printing, and when image editing is performed, storage of input image data and image processing at the time of printing are performed. By using a memory for changing the threshold value for determining the read restriction due to lack of memory when storing image data at the time of input, a predetermined value for image processing for image data to be printed next is changed. You have reserved capacity. By making such a reservation, the memory can be efficiently used as needed, and the printing operation can be smoothly performed according to various states such as the presence or absence of image editing.
[0094]
【The invention's effect】
(1) According to the first aspect of the present invention, the image processing for the image data to be printed next is changed by changing the threshold value for determining the reading restriction due to the lack of memory when storing the image data at the time of input. To reserve a predetermined capacity for Thus, in addition to the storage for editing the image to be printed, the storage of the input compressed image data and the storage of the image data being printed share the same memory. Even if the stored compressed image data exists in the memory and the image data being printed already exists in the memory, the capacity for image editing of the image to be printed cannot be secured. As a result, it is possible to avoid a situation in which the image forming operation is interrupted or stopped due to an error. Further, it is possible to avoid the problem of securing a useless capacity in the memory until the image editing for the image to be printed is actually started. As a result, it is possible to avoid the problem that the storage of new compressed image data is limited.
[0095]
(2) According to the second aspect of the present invention, it is determined whether or not image editing is performed at the time of printing. If image editing is performed, a memory is used for storing input image data and performing image processing at the time of printing. By changing the threshold value for determining the read restriction due to lack of memory when storing the image data at the time of input, a predetermined capacity for image processing for the image data to be printed next is reserved. By doing so, the memory can be efficiently used as needed, and the printing operation can be smoothly performed according to various states such as the presence or absence of image editing.
[0096]
(3) According to the third aspect of the present invention, the storage capacity reserved in the memory is determined by referring to the number of gradations and the print size when performing image formation, and is used for image processing on image data to be printed next. Reserve a given capacity. By doing so, the memory can be efficiently used as needed, and the printing operation can be smoothly performed according to various states such as the presence or absence of image editing.
[0097]
(4) In the invention according to claim 4, when a predetermined capacity for image processing for image data to be printed next is reserved, the job of the image data for which the storage capacity is reserved in the memory is different from other jobs. The control is performed to prohibit the change of the print output order between the two. In this way, the reservation of a predetermined capacity can be effectively handled, the memory can be efficiently used as necessary, and printing can be performed according to various states such as the presence or absence of image editing. The operation can be performed smoothly.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an electrical configuration of a main part of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating a mechanical configuration of a main part of the image forming apparatus according to the embodiment of the present invention;
FIG. 3 is a flowchart illustrating an operation of a control unit according to the embodiment of the present invention.
FIG. 4 is a flowchart illustrating an operation of a control unit according to the embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating an operation of a control unit according to the embodiment of the present invention.
FIG. 6 is an explanatory diagram illustrating an operation of a control unit according to the embodiment of the present invention.
FIG. 7 is an explanatory diagram illustrating an operation of a control unit according to the embodiment of the present invention.
[Explanation of symbols]
20 control means
21 Image processing means
22 Compression means
23 Extension means
24 memory
25 Reading control means
26 Write control means
27 Overall control means

Claims (4)

An image forming apparatus that stores input image data, prints the image on a transfer material after performing image processing as needed,
Storage of input image data, or memory used for image processing required at the time of printing,
Control means for controlling storage of image data in the memory at the time of input and image processing of image data at the time of printing,
The control means changes a threshold value for determining a read limit due to a lack of memory when storing image data at the time of input, thereby reducing a predetermined capacity for image processing on image data to be printed next. make a reservation,
An image forming apparatus comprising: The control means checks whether or not image editing is involved in printing, and reserves a predetermined capacity of the memory when image editing is involved.
The image forming apparatus according to claim 1, wherein: The control means determines the storage capacity reserved in the memory with reference to the number of gradations and the print size when performing image formation,
The image forming apparatus according to claim 1, wherein: Input image data is handled in units of jobs, the next job can be accepted during printing, image data of a plurality of jobs can be stored in the memory, and print output of the job is performed. An image forming apparatus configured to be able to change the order,
The control unit controls a job of image data for which a storage capacity has been reserved in the memory so as to prohibit a change in a print output order from another job.
The image forming apparatus according to claim 1, wherein:

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