JPH11187191A - Device for forming image and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve the burden of a user at the shortage of the remaining capacity of an image storage means without sacrificing work efficiency in an image forming processing. SOLUTION: A device is provided with an image reading device 30 reading image data from an original, an image memory 41 storing image data, a paper sheet tray storing paper sheets, a paper sheet carrying device 51 carrying the paper sheets stored in the paper sheet tray to an image forming position, an image output device 40 forming an image expressed by image data which is stored in an image memory 41 and discharging the paper sheets where the image is formed, an image memory remaining quantity detecting device 61 detecting the remaining quantity (space capacity) of the image memory 41 and a controller 62. Then, the controller 62 judges the priority of carrying the paper sheets by the paper sheet carrying device 51 based on the size of the paper sheets carried by the paper sheet carrying device 51 and the remaining quantity of the image memory 41 so as to control the paper sheet carrying device 51 in accordance with the judgement result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus and an image forming method for forming an image represented by input image data on paper, and more particularly to an image forming technique for coping with a shortage of free space in an image storage memory. About.

[0002]

2. Description of the Related Art Conventionally, a digital copier has a memory for storing image data, so that image data obtained by reading a document image by a scanner unit is temporarily stored in the storage memory, and then stored. A technique for reading out the image data from the memory for obtaining a desired number of copies, or reading image data for a plurality of pages from the storage memory and repeatedly printing the desired number of copies in the page order to obtain a collated copy (copy) Which realize a technique (electronic sort function) for obtaining a product.

[0003] In these digital copying machines, storage of image data is repeated, and when the free space (hereinafter referred to as remaining capacity) of the storage memory becomes insufficient, the process of storing data in the storage memory is interrupted. For example, if the remaining amount of the storage memory is insufficient while the original is being conveyed by the automatic document feeder and read by the scanner unit, the reading is stopped and the original is discharged, or the operation of conveying the original is stopped. When the remaining amount of the storage memory becomes sufficient, control for restarting the document conveyance and the image reading process has been performed.

[0004]

However, if the above-described control is performed when the remaining capacity of the storage capacity memory is insufficient, the user may not be able to accurately grasp the number of originals that could be stored normally, There is a problem that the image data stored in the storage memory is disturbed at the time of resuming the conveyance of the image and the image reading operation. When such a problem occurs, the user feeds a document to be re-set according to his / her own judgment, even though the user cannot accurately know the image data of the document of which page number has a problem. I had to set it on the device. Further, there is a problem that complicated control such as synchronizing the two operations is required when the document is conveyed and the image reading operation is restarted.

In order to solve such a problem, a memory capacity required for storing image data of a document image is calculated, and this memory capacity is compared with the remaining capacity of a storage memory. A technique has been proposed in which a document conveying operation and an image reading operation are not started (for example, Japanese Patent Application Laid-Open No. 5-68151). By the way, in these proposed techniques, a memory capacity required for storing image data is calculated based on a document size (hereinafter, document size) and an image reading magnification. That is, it is necessary to detect the document size before starting the document transport operation.

On the other hand, the size of a document permitted by a copying machine is not limited to one type. In recent years, a plurality of types of document sizes such as a first document size of A4 and a second document size of B5 have been proposed. A copying machine which allows a manuscript having the following is also developed. Even in a copying machine which allows such originals having a plurality of types of original sizes, the situation in which the originals are stacked and set in the automatic original feeder is the same as in the above-described copying machine. Cannot be detected.

Therefore, a copying machine has been developed in which a document size detecting means is provided on a document conveying path from an automatic document feeder to a reading position, and the document size detecting means detects each document size and uses it for various processes. ing. However, according to the method of providing each original size by providing an original size detection unit on the original transport path, the original size cannot be detected unless the original is first transported by the automatic original feeder. That is, when it is determined that the remaining amount of the storage memory is insufficient, the document has already been drawn into the document feeder, and the above-described problem occurs.

Further, in recent years, there has been proposed a technique of shortening a copying work time by simultaneously storing image data of an original image read by a scanner unit in a storage memory and printing the image data. If it is applied, when it is determined that the remaining amount of the storage memory is insufficient, the paper conveyance by the paper conveyance means has already been started and a blank paper is discharged from the copying machine. Is predicted. Of course, if the paper conveyance is started after the detection of the document size, such a situation can be avoided, but the paper conveyance path must be sufficiently short or the document conveyance path must be sufficiently long. The degree of freedom in machine design is reduced. In the first place, increasing the length of the document transport path is contrary to the purpose of shortening the copying operation time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an image forming apparatus which can reduce a burden on a user when the remaining amount of storage memory is insufficient without sacrificing work efficiency. It is an object to provide an image forming method.

[0010]

In order to solve the above-mentioned problems, an image forming apparatus according to the present invention stores image input means for inputting image data, and stores the image data input by the image input means. Image storage means, a paper storage means for storing paper, a paper transport means for transporting the paper stored in the paper storage means to an image forming position, and a table represented by the image data stored by the image storage means. Image forming means for forming an image to be formed on the sheet at the image forming position, free space detecting means for detecting free space in the image storage means, and the size of the sheet conveyed by the sheet conveying means, and A determination is made as to whether or not the sheet can be transported by the sheet transport unit based on the free space detected by the free space detection unit, and the sheet transport unit is determined based on the determination result. It is characterized by comprising a control means for controlling. That is, since the shortage of the free space of the image storage unit can be determined based on the size of the sheet, the free space of the image storage unit can be determined before starting the conveyance of the sheet without sacrificing the image forming work efficiency. Shortage can be determined. Therefore, it is possible to prevent unnecessary conveyance of the sheet when the free space of the image storage unit is insufficient. In addition, whether the control unit determines whether or not the image data can be stored in the image storage unit,
By setting the control target of the control unit to the image storage unit, useless writing to the image storage unit may be prevented.

An image reading means for reading image data from a document at a reading position, a tray for temporarily holding a plurality of documents, and a document feeder for sequentially transporting the plurality of documents on the tray to the reading position Means, the image storage means stores the image data read by the image reading device, and whether or not the control means determines whether or not the document can be conveyed by the document feeding means, an object to be controlled by the control means Is the document feeding means,
Useless conveyance of the document may be prevented.

Further, a paper size detecting means for detecting a size of the paper conveyed by the paper conveying means is provided, and the paper storing means is capable of storing a plurality of sizes of the paper, and the control means comprises a The determination and the control may be performed based on the size of the sheet detected by the size detecting unit and the free space detected by the free space detecting unit. In this case, accurate determination and control can be performed even in the case where the paper size is not fixed.

The control means performs the determination and the control based on a value obtained by multiplying the image data amount corresponding to the size of the sheet by a predetermined number and the free space detected by the free space detecting means. You may do so. In addition, the control unit may determine the predetermined number. For example, the control unit determines the predetermined number according to at least one of the number of image forming surfaces of the paper and the number of image reading surfaces of the document,
A variety of image forming processes may be supported.

Further, if the size of the paper is undecided, the control means determines the size of the paper based on the size of the document and a preset magnification, and determines the size of the paper and the free space. The determination and the control may be performed based on the free space detected by the detecting unit, so that various image forming processes can be supported.

An image reading means for reading image data from a document at a reading position; and a holding unit for temporarily holding a plurality of documents, wherein the plurality of documents held by the holding unit are read one by one from the reading position. Document feed means for transporting the document to the original document, and a document size preliminary detection means for detecting each size of the plurality of documents held by the holding unit, wherein the document feed means detects the size by the document size preliminary detection means. Only the scanned original may be transported from the holding unit to the reading position.

According to another aspect of the present invention, there is provided an image forming method, comprising the steps of: storing input image data in an image storage unit; and storing an image represented by the image data stored in the image storage unit. In the image forming apparatus that forms the image on the sheet at the image forming position, wherein it is determined whether or not the sheet can be transported to the image forming position based on the size of the sheet and the free space of the image storage unit. I have. That is, since the shortage of the free space of the image storage unit can be determined based on the size of the sheet, the free space of the image storage unit can be determined before starting the conveyance of the sheet without sacrificing the image forming work efficiency. Shortage can be determined, and unnecessary conveyance of the sheet can be prevented when the free space of the image storage unit is insufficient.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1: Configuration FIG. 1 is a diagram showing a configuration of a digital copying machine to which an image forming apparatus according to an embodiment of the present invention is applied. The digital copying machine shown in this drawing is roughly composed of four devices. The first device is a control panel 10 including a key for receiving a user's instruction, a display unit for notifying the user of the state of the digital copying machine, and the like.
Also, the second device scans the original by a path passing through the reading position.
An automatic document feeder 20 that conveys sheets one by one; a third device is an image reading device 3 that reads a document image at a reading position
The 0th and 4th devices are image output devices 40 which convey a sheet along a path passing an image forming position, form an image on the sheet at the image forming position, and discharge the sheet.

The automatic document feeder 20 includes a document tray 21 on which a plurality of documents can be set, a document on sensor 22 for detecting that a document has been set on the document tray 21,
A pick-up roll 23 and a document separation roll 24 for separating the documents set on the document tray 21 one by one, and a document for detecting the size of the document while conveying the documents separated by these rolls 23 and 24 to a reading position. The image forming apparatus includes a size sensor 25, a document registration sensor 26, a document discharge tray 27 on which documents discharged after reading are stacked, and the like. The original registration sensor 26
Is located forward of the document size sensor 25 in the document transport direction, and can detect the size of the document in the document transport direction based on the detection result of the document size sensor 25 when the leading edge of the document reaches the detection position of the document registration sensor 26. it can. The size in the other direction can be detected by the position of a document guide (not shown) provided on the document tray 21.

Further, the image reading device 30 performs a predetermined correction or correction on the image data (digital signal) read by the CCD image sensor 31 for optically reading the document image at the reading position and the CCD image sensor 31. It is composed of an image processing unit (not shown) for performing image scaling processing.

Further, the image output device 40 includes an image memory 41 for storing image data read and processed by the image reading device 30, an image memory capacity detecting device 42 for detecting the remaining amount of the image memory 41, and a paper storage device. Paper tray A43a and paper tray B43b, and a paper size sensor A4 for detecting the size of paper in each paper tray.
4a and a paper size sensor B44b, a paper transport roll 45 that transports the paper stored in the selected paper tray one by one to the image forming position, and a paper at the image forming position through an electrophotographic process such as charging, exposure, development, and transfer. An image forming unit 46 for forming an image thereon, a drum 47 provided on a path of the paper, and forming an electrostatic latent image on the drum 47 by converting image data stored in the image memory 41 into laser light. ROS 48, a paper registration sensor 49 for detecting that the paper has reached the image forming position, a paper discharge tray 50 for storing the paper discharged after the image formation, and the like.

In FIG. 1, the image output device 40 includes an image memory remaining amount detecting device 61 for detecting the remaining amount (free space) of the image memory 41, the control panel 10 and the devices 20, 30, and 40. And a control device 62 for controlling. Although not shown, the control device 62 includes a ROM that stores a control program, a CPU that executes the control program, and the like. The control device 62 controls all the operations of the copier by executing the above-described control program. Here, the control device 62 focuses on the functions provided in the control device 62 for performing the electronic sort copy processing. I will explain.

FIG. 2 is a block diagram conceptually showing each part related to the electronic sort copy process, and in FIG. 2, parts common to those in FIG. 1 are denoted by the same reference numerals. As shown in this figure, the control device 62 and other components are connected via a bus 70, and the control device 6
2 transmits and receives instructions to each unit and data from each unit via the bus 70.

FIG. 3 and FIG. 4 are diagrams for explaining the flow of the electronic sort copy processing, and constitute one flowchart by being connected at connection points P1 to P4 in the figure. Hereinafter, the electronic sort copy processing according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 3, in the electronic sort copy processing, the control device 62 first determines whether or not a signal indicating the start of the electronic sort copy has been received from the control panel 10 (step S1). If not received, the determination process is repeated. If received, the document size detection flag FL is set to a value (for example, '0') indicating that the document size detection process is not performed, and the paper size to be used is It is determined whether or not it has already been determined (steps S2 and S3).

The copying machine is provided with a plurality of paper trays, and the display section of the control panel 10 displays the size of paper stored in usable paper trays for each paper tray. Before instructing the start of electronic sort copy, the paper tray (paper size) is not selected.
If the control device 62 has not received the paper tray selection signal, that is, if the determination result in step S3 is "NO", it is determined whether or not the ADF mode is set (step S4). The ADF mode is a mode in which a document is conveyed by the automatic document feeder 20 to make a copy, and whether or not the ADF mode is set is determined by the control device 62 from the document ON sensor 22 of the automatic document feeder 20. Is performed depending on whether or not the signal has been received.

If the decision result in the step S4 is "YES", that is, in the case of the ADF mode, the control device 62 controls the automatic document feeder 20 to start the document conveying process (step S5), and the document size sensor 25, and performs a document size detection process (step S6).
A value (for example, “1”) indicating that the document size detection processing has been performed is set in the document size detection flag FL (step S).
7). It should be noted that the document conveying process indicated by this flowchart is a conveying process from the document tray 21 to the document registration sensor 26. On the other hand, if the determination result of step S4 is "N
In the case of "O", the document transporting process is not performed, and step S6
Document size detection processing is performed. Next, the control device 62
Determines the paper size and paper tray to be used based on the original size detected in step S6 and the copy magnification (hereinafter, set magnification) received from control panel 10 before the start of copying (step S8).

On the other hand, if the result of the determination in step S3 is "YE
In the case of "S", that is, when the paper size to be used (actually, the paper tray) is already determined by operating the control panel 10, the control device 62 uses the paper size sensor corresponding to the paper tray to The size of the paper stored in the paper tray is detected (step S
9). It should be noted that the paper size detection processing can be performed when the paper tray is determined.

When the paper size is determined or detected in step S8 or S9, the control device 62 detects the remaining amount of the image memory 41 by receiving data from the image memory remaining amount detecting device 61 (step S10). Next, the control device 62 performs a comparison process (memory overflow determination process) necessary to determine whether the remaining amount of the image memory 41 is insufficient, that is, whether or not a memory overflow has occurred (step S1). S11). Here, the flow of processing in the memory overflow determination processing is shown in FIG.

As shown in FIG. 5, in the memory overflow determination process, the control device 62
It is determined whether or not the copy mode set in advance by the operation is a copy mode for reading both sides of a document (step S).
12) If this determination result is "NO", it is determined whether the copy mode is a copy mode for printing on both sides of a sheet (step S13). If the determination result in both steps is "NO", that is, if the copy mode is single-sided reading and single-sided printing, the remaining amount of the image memory 41 is compared with the image data amount according to the sheet size ( Step S14) If the determination result of at least one of the above steps is “YES”, that is, if the copy mode is one of double-sided reading, single-sided printing, and double-sided reading double-sided printing, the image memory 41 is used. 2 of image data amount according to remaining amount of paper and paper size
The comparison with the double is performed (step S15). In the control device 62, the image data amount is set in advance for each sheet size.

Referring again to FIG. 3, when the memory overflow determination process is completed, the control device 62 determines whether or not a memory overflow has occurred based on the comparison result in the determination process (step S16). If the determination result is “NO”, the control device 62
Is performed, and a sheet conveyance process for conveying one sheet from the selected sheet tray is performed (step S17).

Next, the control device 62 determines whether or not the size of the document to be transported has already been detected according to the value of the document size detection flag FL (step S18).
Here, the determination result of step S18 is “YES” when the value of the document size detection flag FL is “1”, and “0”
In this case, “NO” is assumed. If the determination result in step S18 is "NO", the document transport process is started if the mode related to document transport is the ADF mode (steps S19 and S20). Then, the control device 62 performs the same document size detection processing as in step S6 (step S6).
21). On the other hand, the determination result of step S18 is “YES”
In this case, the control device 62 sets the document size detection flag FL to '0' (step S22). That is, it is set so that the processes of steps S19 to S21 are performed for the original of the next page. In other words, the result of the determination in step S18 is that the result of the determination in step S3 is "YES" or that the document to be processed is 2 in the ADF mode.
"NO" if the original is the first and subsequent sheets, "NO" if the determination result in step S3 is "NO", and if the original to be processed is the first original in the ADF mode, "YE
S ”.

After completing the processing in step S21 or S22, the control device 62 controls the image reading device 30 to scan the original at the reading position in step S23, and receives the image data obtained thereby. The image data is stored in the image memory 41, and the image output device 40 is controlled in synchronization with the automatic document feeder 20 to transfer an image represented by the image data to a sheet. Let it drain.

Next, the controller 62 controls the document on sensor 2
Then, it is determined whether or not the original of the next page exists based on the signal from step S2, and if so, the process returns to step S10 (step S24). Conversely, if the original described in the following paragraph does not exist, in steps S25 to S28, all the image data stored in the image memory 41 are printed by a preset number of copies by operating the control panel 10, and After deleting the image data, the process returns to step S1. If all the image data has already been printed by the process of step S23, the process proceeds to step S23.
The processing of 25 to S28 is skipped. In this case,
In step S23, the printed image data may be deleted.

On the other hand, if it is determined in step S16 in FIG. 3 that a memory overflow has occurred, the control device 62 causes the display section of the control panel 10 to display a message indicating that a memory overflow has occurred (FIG. 4). (Step S29), and waits until a print start instruction is received from the control 10 (Step S30). Then, when receiving the instruction to start printing, the control device 62 performs the processing of steps S25 to S28.

In the copy mode other than the single-sided reading and single-sided printing, the transport timing between the document and the sheet is set such that in the case of the single-sided reading and double-sided printing, two sheets of the original are printed on the sheet
In the case of single-sided printing and two-sided reading, two sheets of paper are adjusted for one document, and in the case of two-sided reading and double-sided printing, one sheet of paper is adjusted for one document.

2: Operation Next, the operation of the copying machine having the above-described configuration will be described by focusing on the electronic sort copy processing. FIG. 6 is a time chart for explaining the operation of each section of the copying machine, and shows an example of the operation of each section in the electronic sort copy process (ADF mode) when the paper size is determined in advance. In this figure, the level of the level corresponds to the activation / deactivation of each unit or the active / inactive of the output result of each unit.

First, the controller 62 controls the first document.
Determines that "memory overflow has not occurred", the paper transport roll 45 starts operating, and one sheet is fed from the selected paper tray. When the sheet reaches the detection position of the sheet registration sensor 49, the detection result of the sheet registration sensor 49 becomes active, and the operation of the sheet transport roll 45 stops. Also, the paper transport roll 4
During the operation of 5, the document separating roll 24 starts operating, and
The first document is sent out from the document tray 21. When the document reaches the detection position of the document registration sensor 26, the detection result of the document registration sensor 26 becomes active, and the paper transport roll 45 resumes its operation. As a result, the sheet and the document are conveyed in synchronization with each other. Then, when the document reaches the reading position, the scanning process for the document is started, the image data of the scan result is written to the image memory 41, and the printing process (image forming process) for the image data is started. . In the example shown in this figure, the scanning process, the writing process to the image memory 41, and the printing process end almost simultaneously. The detection results of the original registration sensor 26 and the paper registration sensor 49 become inactive when the trailing edge of the original passes the detection position.

When the scanning process for the first document, the writing process for the image memory 41, and the printing process are completed, the process for the second document is started after a predetermined short time has elapsed. In the example shown in this figure, the control device 62 also determines that "memory overflow has not occurred" for the second document, and the processing for the document is the same as the processing for the first document.

When the scanning process for the second document, the writing process to the image memory 41, and the printing process are completed, the process for the third document is started after a lapse of a predetermined short time. In the example shown in this figure, for the third document, the control device 62 has determined that “memory overflow has occurred”, the paper transport roll 45 does not start operation, and the copier is instructed by the user. I will wait. At this point, the third sheet remains in the selected paper tray without being transported by the paper transport roll 45, and
The document tray 21 holds a third document on a document separation roll 24.
Remains without being transported. In the image memory 41, image data for the second original is left. Therefore, the user operates the control panel 10.
Is operated to input an instruction to perform printing, the copy corresponding to the second original is normally output by a preset number of copies, and after the image data in the image memory 41 is deleted, the copy is used. When the user operates the control panel 10 to restart copying, the copying process for the third original is normally performed.

3: Supplement As described above, according to the copying machine, the image memory 4
Even if the remaining amount of the image data 1 is insufficient, the image data in the image memory 41 is not disturbed, the blank sheet is not discharged, and further, a document that cannot store the image data in the image memory 41 is placed in the apparatus. Copy processing can be performed without being pulled in. However, if the paper size has not been set in advance, the paper size is determined in consideration of the set magnification after detecting the original size of the first single document. If the image data cannot be written to the image memory 41, the user must perform a journalizing operation.

In the above-described copying machine, the original size is detected in the course of transporting the original so as to cope with the case where the size of each page of the original is different. The original size sensor may be provided to detect the original size. However, in this case, it is not possible to cope with the case where the size of each page of the document is different, and the size of the document for each page is the size of the largest size page.

If the size of each original can be detected without drawing the original from the original tray into the copying machine,
The determination of the occurrence of the memory overflow may be performed based on the document size. For example, as shown in FIG. 7, the document tray has a two-stage configuration, and one document is transported from the document tray B 21b to the document tray A 21a.
The original may be drawn into the copying machine after the original size is detected in 1a, and then the original of the next page may be conveyed from the original tray B 21b to the original tray A 21a.

In FIG. 7, parts common to those in FIG. 1 are denoted by the same reference numerals. The difference between the automatic document feeder 20a shown in FIG. 7 and the automatic document feeder 20 shown in FIG. The point that the document size sensor 25 is removed, the point that a document tray A 21 a is provided instead of the document tray 21,
This is the point that a document tray B21b is provided in front of the document tray A21a. The document tray A21a differs from the document tray 21 in that a document size sensor group 28 including a plurality of sensors arranged at predetermined positions is provided instead of a document guide (not shown). The sensor group 28 detects the size of the document on the document tray A21a. The document tray B21b has substantially the same configuration as the document tray 21, and the only difference between the former and the latter is that the document is transported to the document tray A21a instead of in the apparatus.

The example in which the present image forming apparatus is applied to a copying machine has been described above. However, the present invention is not limited to this, and can be applied to any apparatus that prints an input image on paper and outputs it. In particular, application to an apparatus in which the size of a document is variable is effective. For example, when the present invention is applied to a network printer, a document size is generally included in input image data, so that the document size can be used. Further, the paper storing means for storing the paper may be a manual feed tray capable of storing a plurality of papers. When manually feeding paper one by one,
The means for temporarily storing one manually inserted sheet corresponds to the sheet storage means. Needless to say, the technical scope of the invention according to the present application is not limited to the above-described embodiment, and various modifications may be made to the above-described embodiment to implement the invention described in the claims. can do. It is obvious from the description of the claims that such an invention belongs to the technical scope of the invention according to the present application.

[0045]

As described above, according to the present invention,
Since the shortage of the free space of the image storage unit can be determined based on the size of the sheet, the shortage of the free space of the image storage unit can be determined before starting the conveyance of the sheet without sacrificing the work efficiency. Therefore, when the free space of the image storage unit is insufficient, it is possible to prevent unnecessary conveyance of the paper or the document and unnecessary writing to the image storage unit. Therefore,
The burden on the user when the free space (remaining amount) of the image storage unit is insufficient can be reduced without sacrificing work efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a digital copying machine to which an image forming apparatus according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram conceptually showing each part related to an electronic sort copy process extracted from the copying machine.

FIG. 3 is a diagram illustrating a flow of an electronic sort copy process performed by the copying machine.

FIG. 4 is a diagram illustrating a flow of an electronic sort copy process performed by the copying machine.

FIG. 5 is a diagram showing a processing flow in a memory overflow determination process of the copying machine.

FIG. 6 is a time chart for explaining the operation of each section of the copying machine.

FIG. 7 is a diagram illustrating a modification of the copying machine.

[Explanation of symbols]

10 control panel, 20 automatic document feeder,
30 image reading device, 40 image output device, 61
Image memory remaining amount detection device, 62 ... Control device, 43a, 4
3b: paper size sensor, 25: original size sensor

Claims (11)

[Claims] An image input unit for inputting image data; an image storage unit for storing the image data input by the image input unit; a paper storage unit for storing a sheet; A sheet conveying unit that conveys the sheet to an image forming position; an image forming unit that forms an image represented by the image data stored by the image storage unit on the sheet at the image forming position; A vacant capacity detecting means for detecting a vacant capacity of a storage means, and the paper transported by the paper transporting means based on a size of the paper transported by the paper transporting means and the vacant capacity detected by the empty capacity detecting means. An image forming apparatus comprising: a control unit configured to determine whether or not the sheet can be transported, and to control the sheet transport unit according to a result of the determination. 2. The image processing apparatus according to claim 1, wherein the control unit determines whether the image data can be stored in the image storage unit, and a control target of the control unit is the image storage unit. An image forming apparatus according to claim 1. An image reading means for reading image data from a document at a reading position; a tray for temporarily holding a plurality of documents; and a document feeder for sequentially transporting the plurality of documents on the tray to the reading position. The image storage means stores the image data read by the image reading device; the control means determines whether or not the document can be transported by the document feeding means; and the control means 2. The image forming apparatus according to claim 1, wherein the control target is the document feeding unit. 4. A sheet size detecting means for detecting a size of the sheet conveyed by the sheet conveying means, wherein the sheet storing means can store the sheets of a plurality of sizes, 2. The image forming apparatus according to claim 1, wherein the determination and the control are performed based on the size of the sheet detected by the sheet size detecting unit and the free space detected by the free space detecting unit. apparatus. 5. The control unit performs the determination and the control based on a value obtained by multiplying an image data amount according to the size of the sheet by a predetermined number and the free space detected by the free space detection unit. The image forming apparatus according to claim 1, wherein: 6. The image forming apparatus according to claim 5, wherein the control unit determines the predetermined number according to the number of image forming surfaces on the sheet. 7. The image forming apparatus according to claim 5, wherein the control unit determines the predetermined number according to the number of image reading surfaces of the document. 8. The apparatus according to claim 5, wherein the control unit determines the predetermined number according to the number of image forming surfaces of the paper and the number of image reading surfaces of the document.
An image forming apparatus according to claim 1. 9. The control unit, when the size of the paper is undecided, determines the size of the paper based on the size of the document and a preset magnification, and determines the size of the paper and the empty space. The image forming apparatus according to claim 1, wherein the determination and the control are performed based on the free space detected by a capacity detecting unit. 10. An image reading means for reading image data from a document at a reading position, and a holding portion for temporarily holding a plurality of documents, wherein the plurality of documents held by the holding portion are read one by one from the reading position. And a document size pre-detection unit that detects each size of the plurality of documents held in the holding unit. The document feed unit detects the size by the document size pre-detection unit. The image forming apparatus according to claim 1, wherein only the read original is transported from the holding unit to the reading position. 11. An image forming apparatus which stores input image data in an image storage means and forms an image represented by the image data stored in the image storage means on a sheet at an image forming position. And determining whether or not the sheet can be transported to the image forming position based on a size and a free space of the image storage unit.