JP3502214B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a transfer sheet by forming a latent image on a photoconductor, and more specifically, it stores image information in an image storage means such as a memory. And an image forming apparatus capable of repeatedly forming an image in page order.

[0002]

2. Description of the Related Art Generally, in an electrophotographic image forming apparatus (image forming apparatus), an electric signal (image information) is converted according to the density of a document and a laser beam or the like is used according to the image signal. An electrostatic latent image is formed on the photosensitive drum.

Then, the electrostatic latent image is developed into a toner image and then transferred to a transfer sheet, and the toner image on the transfer sheet is heated and fused and fixed by a heater of a fixing device. As such an image forming apparatus, there are a digital copying machine having a document reading section, a laser printer having no reading section and forming an image according to image information from the outside.

By the way, in a copying machine, RDH (Reci
There is a circulating document feeder called rculating Document Handler). This RDH mechanically circulates and reads a document for a required number of times.

When such an RDH is used, the manuscript for the required number of copies can be easily copied, but since the manuscript is circulated and read for the number of times of the required number of copies, it takes a long time to read and the manuscript is easily damaged. Have

Therefore, a system called electronic RDH has come to be used. In this electronic RDH, the document is read once and stored in the image storage unit, and the required number of copies are formed.

Therefore, the number of readings of the original document is reduced, the time is shortened, and the pain of the original document can be minimized. Further, in the case of printing a plurality of the same pages, it is possible to save the time for developing the image for each page and maximize the performance of the number of printable sheets per time that image forming has. .

FIG. 6 is a block diagram showing the structure of image formation provided with an electronic RDH. This image forming apparatus has both a function as a copying machine and a function as a printer. The external device 10 is a host computer, a printer controller, or the like, and supplies image information to the image forming 20.

The image forming apparatus 20 includes an image reading unit 30 for reading an image of a document or the like, an I / F control unit 40 for controlling an interface with the external device 10, and an image processing unit for performing various kinds of image processing and image development. 50, compression of image information /
An image compression / expansion unit 60 that expands and stores, and an image forming unit 70 that forms a toner image on a recording paper by developing, transferring, and fixing after forming a latent image on a photosensitive drum by laser light according to the expanded image information. , A controller unit 80 for controlling each unit, and an operation unit 90 for inputting various instructions.

FIG. 7 is a block diagram showing the function of an image forming apparatus equipped with an electronic RDH as a printer.
The same parts as those in FIG. 6 are designated by the same reference numerals. The image compression / expansion unit 60 includes an image compression unit 61 that compresses image information.
An image storage unit 62 for storing the compressed image information,
The image decompression unit 63 that decompresses the compressed image information.

In such an image forming apparatus, the image information read by the image reading unit 30 and the image information supplied from the external device 10 are compressed by the image compression unit 61 and stored in the image storage unit 62. Then, the required page is displayed in the image storage unit 62.
Read from the image processing unit 5 and expanded by the image expansion unit 63.
Supply to 0. The image processing unit 50 develops the image information from the image expansion unit 63 page by page and supplies it to the image forming unit 70 to execute image formation.

[0012]

In this electronic RDH,
A memory is used as the image storage unit 62, and the image information of the document is stored in this memory. in this case,
There is a limit to the memory capacity, and image compression technology is used to effectively use this memory capacity.

That is, since the above-mentioned advantage can be exhibited by reading a manuscript having a large number of pages into a memory having a limited capacity, the image information is compressed in data, temporarily stored in the memory, and read from the memory. The data is expanded at this time.

Although the number of pages which can be stored in the memory is increased by using such image compression, there is a problem that a part of the image information is lost and the gradation reproducibility is deteriorated. Although such a point does not pose a problem in a character image, deterioration in image quality may occur in a high-quality image having a halftone.

Therefore, an object of the present invention is to provide an image forming apparatus capable of dealing with a high quality image even when an image is formed by an image forming apparatus equipped with an electronic RDH.

[0016]

That is, the present invention which constitutes means for solving the problems is as described in the following (1) to (3).

(1) A first invention is an image forming apparatus for forming an image on a transfer paper by forming a latent image on a photoconductor, and an image compression unit for compressing image information and a page. An image storage unit capable of storing unit image information, an image decompression unit for decompressing compressed image information, a unit for determining the content of a document from a character code or page description language included in the image information, and an image The information is stored in the image storage means without using the image compression unit and the image expansion unit and is used for image formation.
Image recording is performed by compressing the mode 2 and image information in the image compression unit.
After storing in the memory, the image is read out from the image memory
An image forming apparatus comprising: a control unit that controls two types of modes, a first mode that is expanded by an expansion unit and used for image formation, according to a result of the determination.

According to the invention of the image forming apparatus, in the image formation of a plurality of copies, the first mode and the second mode are selectively used according to the determination result of the content of the image information to perform compression / expansion. It is possible to realize the case of forming and the case of forming an image without performing compression / expansion. In this case, according to the second mode in which compression / decompression is not performed, deterioration of image information does not occur, and a high-quality image can be reproduced.

(2) A second invention is an image forming apparatus for forming an image on a transfer paper by forming a latent image on a photoconductor, and an image compression section for compressing image information and a page. An image storage unit capable of storing unit image information, an image decompression unit for decompressing compressed image information, a unit for determining the content of a document from a character code or page description language included in the image information, and an image The information is stored in the image storage means without using the image compression unit and the image expansion unit and is used for image formation.
And second mode, the image SL by compressing the image information by the image compression unit
After storing in the memory, the image is read out from the image memory
Control of three types of modes, that is, a first mode that is used for image formation after being expanded by the expansion unit and a third mode that outputs image information to the image forming unit without passing through the image storage means is based on the above determination. An image forming apparatus, comprising: a control unit that operates according to a result.

According to the invention of this image forming apparatus, compression / expansion can be performed by properly using the first mode and the second and third modes in accordance with the determination result of the content of the image information in the image formation of a plurality of copies. It is possible to realize the case where the image is formed by performing the image forming and the case where the image is formed without performing the compression / expansion. In this case, according to the second and third modes in which compression / decompression is not performed, deterioration of image information does not occur, and a high-quality image can be reproduced.

In the case of forming an image through the image storage means by selectively using the first and second modes and the third mode according to the result of the determination of the content of the image information in the image formation of a plurality of copies. It is possible to realize the case where an image is formed without using the image storage means. In this case, in the case of the first and second modes via the image storage means, the image storage means functions as a buffer, so that efficient image formation can be realized when the transfer speed of image information from the outside is slow. Further, in the case of the third mode in which the image storage unit is not used, efficient image formation can be realized when the transfer speed of image information from the outside is high.

(3) A third aspect of the present invention is an image forming apparatus that forms an image on a transfer sheet by forming a latent image on a photoconductor, and an image compression unit that compresses image information and a page. An image storage unit capable of storing unit image information, an image decompression unit for decompressing compressed image information, a unit for determining the content of a document from a character code or page description language included in the image information, and an image The information is compressed by the image compression unit and stored in the image storage unit, and then read out from the image storage unit
Control of two kinds of modes, a first mode used for image formation after being expanded by the expansion unit and a third mode for outputting image information to the image forming unit without passing through the image storage unit, is performed according to the result of the determination. The image forming apparatus is provided with:

According to the invention of the image forming apparatus, in the image formation of a plurality of copies, the first mode and the third mode are selectively used according to the determination result of the content of the image information, and the image is stored via the image storage means. It is possible to realize a case of forming an image and a case of forming an image without using an image storage unit. In this case, when the image storage unit is used, the image storage unit functions as a buffer, so that efficient image formation can be realized when the transfer speed of the image information from the outside is slow. Further, when the image storage means is not used, efficient image formation can be realized when the transfer speed of image information from the outside is high.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. <Structure> FIG. 1 is a block diagram showing a structure of a main part of an image forming apparatus according to an embodiment of the present invention. An image forming apparatus having both a function as a copying machine and a function as a printer will be described here.

The external device 11 is a host computer or the like and supplies image information to the image forming 20. The image forming apparatus 21 includes an image reading unit 30 that reads an image of a document or the like, an I / F control unit 40 that performs interface control with the external device 10, an image processing unit 51 that performs various types of image processing and image development, An image compression unit 61 that compresses image information, an image storage unit 62 that stores compressed image information, and an image decompression unit 6 that decompresses compressed image information.
3, a selector 64 for selectively passing either uncompressed image information or image information compressed by the image compression unit 61, and a latent image on the photosensitive drum by a laser beam according to the expanded image information. An image forming unit 70 that forms a toner image on recording paper by developing, transferring, and fixing after forming
And a controller section 81 for controlling each section, and an operation section 90 for inputting various instructions.

The selection state of the selector 64 is controlled by the controller section 81, and the image processing section 51 is also controlled.
Also in this case, the controller unit 81 controls to selectively expand the image information from the image storage unit 62 and the image information from the image expansion unit 63.

That is, the controller section 81 uses the first mode and the second mode properly according to the content of the image information, thereby performing the compression / expansion to form an image and the compression / expansion without the compression / expansion. The control is performed to realize the case of forming an image.

FIG. 2 is a block diagram showing a data structure of image information in the external device 10, the I / F control unit 40 and the image processing unit 51. In FIG. 2, the external device 10 and the I / F
It is connected to the control unit 40 in accordance with the specifications conforming to the Centronics interface. That is, the external device 1
Between 0 and the interface control unit 40, 8-bit parallel data (DATA 1 to 8), strobe pulse (/ STROBE) for reading data, and busy signal (/ BUSY) indicating the operating state of the printer are minimum. It is connected.

Further, the I / F control unit 40 sends the synchronizing signals (/ OPVV, / OPIND, / OPCLK) together with the 8-bit parallel data (P_DATA1 to 8) to the image processing unit 51. On the other hand, the image processing unit 51
The sync signal (/ IPVV, / I
PIND, / IPHV, / IPCLK) is transmitted.

It should be noted that, in each of the above-mentioned signals, a signal having a name starting with "/" indicates that it is LOW active. <Operation> The image forming apparatus 21 can perform both an operation as a copying machine and an operation as a printer.
In this embodiment, the operation of the printer will be described.

First mode: In such an image forming apparatus, when no particular setting is made, or I / F
When the normal mode is designated by the judgment by the control unit 40 or the controller 81 or the mode designation from the external device 11, the image information supplied from the external device 11 is compressed by the image compression unit 61 (FIG. 1). It is stored in the storage unit 62.

Then, a page required according to the print request is read from the image storage unit 62, expanded by the image expansion unit 63 (FIG. 1 ') and supplied to the image processing unit 50. The image processing unit 50 develops the image information from the image expansion unit 63 page by page and supplies it to the image forming unit 70 to execute image formation.

That is, it is possible to perform the same operation as a conventional printer having an electronic RDH. Second mode: When the high-quality print mode is designated by the determination by the I / F control unit 40 or the controller 81, the mode designation by the operation unit 90 or the mode designation by the external device 11, the high-quality print mode is supplied from the external device 11. With respect to the image information, the selector 64 bypasses the image compression unit 61, and the image information in the uncompressed state (FIG. 1) is stored in the image storage unit 62.

Then, a required page is read from the image storage unit 62 in response to the print request and supplied to the image processing unit 50. That is, the image processing unit 51 reads the image information (FIG. 1 ′) from the image storage unit 62 without passing through the image expansion unit 63. The image processing section 50 develops the image information from the image storage section 62 page by page and supplies it to the image forming section 70 to execute image formation.

That is, it is possible to operate as a printer which does not have an electronic RDH but has a buffer. According to the second mode in which such compression and decompression are not performed, deterioration of image information does not occur, and a high quality image can be reproduced.

In this case, the image storage unit 62 operates as a buffer by interposing the image storage unit 62 when performing high-quality printing in the second mode. Therefore, efficient image formation can be realized when the transfer speed of the image information from the external device 11 is low (when an interface having a low transfer speed is used).

The broken line in the image processing section 51 in FIG. 1 schematically shows the flow of image information, and actually, various processing circuits are passed in the middle of the broken line. Although the selector 64 is provided only on the input side of the image storage unit 62 here, it may be provided on the output side of the image storage unit 62.

<Structure> FIG. 3 is a block diagram showing the structure of the main part of the image forming apparatus according to the second embodiment of the present invention. An image forming apparatus having both a function as a copying machine and a function as a printer will be described here.

The external device 12 is a printer controller or the like, and supplies the expanded image information to the image forming 20. The image forming apparatus 21 includes an image reading unit 30 that reads an image of a document or the like, and an external device 1.
An I / F control unit 40 that performs interface control with the
An image processing unit 51 that performs various image processing and image expansion, an image compression unit 61 that compresses image information, an image storage unit 62 that stores compressed image information, and an image decompression that decompresses the compressed image information. A portion 63, a selector 64 for selectively passing either uncompressed image information or image information compressed by the image compression portion 61, and a latent image on the photosensitive drum by laser light according to the expanded image information. The image forming section 70 forms a toner image on the recording sheet by developing, transferring, and fixing after forming, the controller section 81 for controlling each section, and the operation section 90 for inputting various instructions.

The selection state of the selector 64 is controlled by the controller section 81. In addition, the image processing unit 51
In the above, the image information from the image storage unit 62 and the image information from the image expansion unit 63 can be selectively expanded, and further,
When the expanded image information is supplied from the I / F control unit 40, it is controlled by the controller unit 81 so that it can be directly supplied to the image forming apparatus 70.

That is, the controller unit 81 uses the first mode to the third mode in accordance with the contents of the image information to form an image without compression / expansion when the image is formed by compression / expansion. The control is performed by switching three modes, that is, when the image is formed by using the storage unit 62 as a buffer and when the developed image information is formed without the image storage unit 62.

In the configuration using the printer controller 12, a computer or the like is connected before the printer controller 12, and the printer controller 12 receives the image information, expands it, and transfers it to the I / F control unit 40. Has become.

In this configuration, the printer controller 12
Between the I / F controller 40 and the standard Centronics
A dedicated high-speed interface can be used instead of the interface.

<Operation> The image forming apparatus 21 can perform both an operation as a copying machine and an operation as a printer. In this embodiment, the operation as a printer will be described.

First mode: In such an image forming apparatus, when no particular setting is made, or the I / F
When the normal mode is designated by the judgment by the control unit 40 or the controller 81 or the mode designation from the external device 12, the image information supplied from the external device 12 is compressed by the image compression unit 61 (FIG. 1). It is stored in the storage unit 62.

Then, a page required according to the print request is read from the image storage unit 62, expanded by the image expansion unit 63 (FIG. 1 '), and supplied to the image processing unit 50. The image processing unit 50 develops the image information from the image expansion unit 63 page by page and supplies it to the image forming unit 70 to execute image formation.

That is, it is possible to perform the same operation as a conventional printer having an electronic RDH. Second mode: When the high-quality print mode is designated by the determination by the I / F control unit 40 or the controller 81, the mode designation by the operation unit 90 or the mode designation by the external device 12, the high-quality print mode is supplied from the external device 12. With respect to the image information, the selector 64 bypasses the image compression unit 61, and the image information in the uncompressed state (FIG. 1) is stored in the image storage unit 62.

Then, a page required according to the print request is read from the image storage unit 62 and supplied to the image processing unit 50. That is, the image processing unit 51 reads the image information (FIG. 1 ′) from the image storage unit 62 without passing through the image expansion unit 63.

The image processing section 50 develops the image information from the image storage section 62 page by page and supplies it to the image forming section 70 to execute image formation. That is, it is possible to operate as a printer having a buffer instead of the electronic RDH. According to the second mode in which such compression and decompression are not performed, deterioration of image information does not occur, and a high quality image can be reproduced.

In this case, the image storage unit 62 operates as a buffer by interposing the image storage unit 62 when performing high-quality printing in the second mode. Therefore, efficient image formation can be realized when the transfer speed of the image information from the external device 12 is slow (when an interface having a slow transfer speed is used).

When image information waiting to be printed has already been stored in the image storage unit 62, image information in this mode is stored after that, so that printing is executed in the order of print jobs.

Further, the broken line in the image processing section 51 in FIG. 1 schematically shows the flow of image information, and actually, various processing circuits are passed in the middle of the broken line. Third mode: When the high-quality print mode is designated by the determination by the I / F control unit 40 or the controller 81, the mode designation by the operation unit 90 or the mode designation by the external device 12, the external device 12 has already The controller 81 confirms that the expanded image information is supplied.
Is recognized, the image information supplied from the external device 12 is bypassed inside the image processing unit 51 (see FIG.
), And supplies it to the image processing unit 50. That is, the image processing unit 51 outputs the image to the image forming unit 70 without expanding the image.

That is, it is possible to operate as a printer having neither an electronic RDH nor a buffer. According to the third mode that does not use such compression / expansion and buffer, it is possible to reproduce a high-quality image without causing deterioration of image information.

At the time of printing in the third mode, the printer controller 12 determines that the image is a high-quality image during image development, and the controller unit 81 receiving the determination result prints in the third mode. To each section. As a result, the image information from the I / F control unit 40 is immediately bypassed in the image processing unit 50 and output to the image forming unit 70. Therefore, the printing in the third mode is executed by jumping over the image information waiting to be printed that remains in the image storage unit 62.

Since the buffer is not used in this way, efficient image formation can be realized when the transfer speed of the image information from the external device 12 is high (using a printer controller or an interface having a high transfer speed). .

The broken line in the image processing section 51 in FIG. 3 schematically shows the flow of image information in the third mode. <Structure> FIG. 3 is a block diagram showing the structure of the main part of an image forming apparatus according to the third embodiment of the present invention. An image forming apparatus having both a function as a copying machine and a function as a printer will be described here.

The external device 12 is a printer controller or the like, and supplies the expanded image information to the image forming 20. The image forming apparatus 21 includes an image reading unit 30 that reads an image of a document or the like, and an external device 1.
An I / F control unit 40 that performs interface control with the
An image processing unit 51 that performs various image processing and image expansion, an image compression unit 61 that compresses image information, an image storage unit 62 that stores compressed image information, and an image decompression that decompresses the compressed image information. A unit 63, an image forming unit 70 that forms a toner image on recording paper by developing, transferring, and fixing after forming a latent image on a photosensitive drum by a laser beam according to the developed image information, and a controller unit 81 that controls each unit.
And an operation unit 90 for inputting various instructions.

The controller 81 controls the image forming apparatus 70 so that it can directly supply the expanded image information from the I / F controller 40. That is, the controller unit 81 selectively uses the first mode and the third mode according to the content of the image information to perform compression / expansion to form an image, and the expanded image information to the image storage unit 62. The control is realized by switching the two modes of the case of forming an image without the intervention of.

In the configuration using the printer controller 12, a computer or the like is connected before the printer controller 12, and the printer controller 12 receives the image information, expands it, and transfers it to the I / F control unit 40. Has become.

In this configuration, the printer controller 12
Between the I / F controller 40 and the standard Centronics
A dedicated high-speed interface can be used instead of the interface.

<Operation> The image forming apparatus 21 can perform both an operation as a copying machine and an operation as a printer. In this embodiment, the operation as a printer will be described.

First mode: In such an image forming apparatus, when no particular setting is made, or the I / F
When the normal mode is designated by the judgment by the control unit 40 or the controller 81 or the mode designation from the external device 12, the image information supplied from the external device 12 is compressed by the image compression unit 61 (FIG. 1). It is stored in the storage unit 62.

Then, a page required according to the print request is read from the image storage unit 62, expanded by the image expansion unit 63 (FIG. 1 ') and supplied to the image processing unit 50. The image processing unit 50 develops the image information from the image expansion unit 63 page by page and supplies it to the image forming unit 70 to execute image formation.

That is, it is possible to perform the same operation as the conventional printer having the electronic RDH. Third mode: When the high-quality print mode is designated by the determination by the I / F control unit 40 or the controller 81, the mode designation by the operation unit 90 or the mode designation by the external device 12, the external device 12 has already The controller 81 confirms that the expanded image information is supplied.
Is recognized, the image information supplied from the external device 12 is bypassed inside the image processing unit 51 (see FIG.
), And supplies it to the image processing unit 50. That is, the image processing unit 51 outputs the image to the image forming unit 70 without expanding the image. Therefore, the printing in the third mode is executed by jumping over the image information waiting to be printed that remains in the image storage unit 62.

That is, it is possible to operate as a printer having neither an electronic RDH nor a buffer. According to the third mode that does not use such compression / expansion and buffer, it is possible to reproduce a high-quality image without causing deterioration of image information.

Since the buffer is not used in this way, efficient image formation can be realized when the transfer speed of the image information from the external device 12 is high (using a printer controller or an interface having a high transfer speed). .

The broken line in the image processing section 51 in FIG. 3 schematically shows the flow of image information in the third mode. That is, in the third embodiment, the second mode is omitted, but when a device such as a printer controller capable of transferring developed image information at high speed is connected as an external device, The third mode may be used for high quality printing.

<Determination of High Quality Print> FIG. 5 (a)-
(E) is an explanatory view schematically showing the state of various originals.
Here, FIG. 5A is an original composed of only characters, and FIG. 5B is an original in which characters and photographs (images including halftones, halftone images, etc.) are mixed. Reference numeral 5 (c) is a document composed only of photographs (images including halftones, halftone images, etc.). Further, FIGS. 5D and 5E are also originals in which characters and photographs are mixed.

The printer controller 12 or the I / F control unit 40 determines the content of such a document. The printer controller 12 may make the determination from the histogram of the density distribution or the like when performing the image expansion. Also,
The I / F control unit 40 makes a determination based on the character code, page description language, etc. included in the image information sent from the external device 11.

Upon receipt of the determination result, the controller section 81 gives an instruction to each section to specify the printing mode. That is, since the original of characters as shown in FIG. 5A does not have a halftone, the compressed image information is stored in the image storage unit 62 and the efficient printing in the first mode is executed. . For originals including photographs as shown in FIGS. 5B to 5E, printing without image compression is performed with emphasis on reproduction of halftones (second mode or third mode described above). To do.

[0071] Also, even if according to the judgment a document having a photograph, performing an instruction input good print efficiency according to the first mode giving priority to from the command or the operation unit 90 from the external device Is also possible.

[0072]

As described in detail above, according to the present invention, the following effects can be obtained. (1) In the invention of the first image forming apparatus, in the image formation of a plurality of copies, compression / expansion is performed by selectively using the first mode and the second mode according to the determination result of the content of the image information. It is possible to realize the case of forming an image by performing the image forming and the case of forming the image without performing compression / expansion. in this case,
According to the second mode in which the compression / decompression is not performed, the image information is not deteriorated and a high quality image can be reproduced.

(2) In the invention of the second image forming apparatus, in the image formation of a plurality of copies, the first mode and the second and third modes are selectively used according to the determination result of the content of the image information. It is possible to realize a case where an image is formed by performing compression / expansion and a case where an image is formed without performing compression / expansion. In this case, according to the second and third modes in which compression / decompression is not performed, deterioration of image information does not occur, and a high-quality image can be reproduced. Further, in the image formation of a plurality of sets, by selectively using the first and second modes and the third mode according to the determination result of the content of the image information, the case where the image is formed through the image storage means and the case where the image is stored It is possible to realize a case where an image is formed without using any means. In this case, in the case of the first and second modes via the image storage means, the image storage means functions as a buffer, so that efficient image formation can be realized when the transfer speed of image information from the outside is slow. Further, in the case of the third mode in which the image storage unit is not used, efficient image formation can be realized when the transfer speed of image information from the outside is high.

(3) In the invention of the third image forming apparatus, in the image formation of a plurality of copies, the first mode and the third mode are selectively used according to the determination result of the content of the image information, thereby storing the image. It is possible to realize the case of forming an image through the means and the case of forming the image without using the image storage means. In this case, when the image storage unit is used, the image storage unit functions as a buffer, so that efficient image formation can be realized when the transfer speed of the image information from the outside is slow. Further, when the image storage means is not used, efficient image formation can be realized when the transfer speed of image information from the outside is high.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a main part of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an image forming apparatus according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of an image forming apparatus according to a third exemplary embodiment of the present invention.

FIG. 5 is an explanatory diagram showing types of originals determined in the embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional image forming apparatus.

FIG. 7 is a block diagram showing a detailed configuration of a main part of a conventional image forming apparatus.

[Explanation of symbols]

11 External equipment 21 Image formation 30 Image reading unit 40 I / F control unit 51 Image processing unit 61 Image compression unit 62 image storage unit 63 Image decompression unit 64 selector 70 Image forming unit 81 Controller section 90 Control

Claims (3)

(57) [Claims] 1. An image forming apparatus for forming an image on a transfer sheet by forming a latent image on a photoconductor, the image compressing section for compressing image information, and the image information for each page can be stored. Image storage means, an image decompression section for decompressing compressed image information, a means for determining the content of the original from the character code and page description language included in the image information, and image information for the image compression section and image. The second mode and the image information stored in the image storage means and used for image formation without passing through the decompression unit are compressed by the image compression unit and stored in the image storage unit.
After that, it is read from the image storage means and decompressed by the image decompression unit.
And a control unit that controls two kinds of modes of the first mode used for image formation according to the result of the determination. 2. An image forming apparatus for forming an image on a transfer sheet by forming a latent image on a photoconductor, the image compressing section for compressing image information, and the image information for each page can be stored. Image storage means, an image decompression section for decompressing compressed image information, a means for determining the content of the original from the character code and page description language included in the image information, and image information for the image compression section and image. A second mode which is stored in the image storage means and used for image formation without passing through the decompression unit;
The image information is compressed by the image compression unit and stored in the image storage means.
After that, it is read from the image storage means and decompressed by the image decompression unit.
Control of three types of modes, that is, a first mode used for image formation and a third mode in which image information is output to the image forming unit without passing through the image storage unit, according to the result of the determination. An image forming apparatus comprising: a control unit. 3. An image forming apparatus for forming an image on a transfer sheet by forming a latent image on a photoconductor, the image compressing section for compressing image information, and the image information for each page can be stored. Image storage means, an image decompression section for decompressing compressed image information, a means for determining the content of the original from the character code and page description language included in the image information, and the image information compression section for compressing the image information. And store it in the image storage means
After that, it is read from the image storage means and decompressed by the image decompression unit.
And a control unit that controls two types of modes, a first mode used for image formation and a third mode in which image information is output to the image formation unit without passing through the image storage unit, according to the result of the determination. An image forming apparatus comprising: