JP2000259047A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity and to make maintainable high image quality by controlling the switching of a system speed mode based on mode switching time, image information after the present image, and so on in the case where, when the present image is formed, the previous mode is low speed mode and the present image can be processed at a high speed. SOLUTION: A second original (present original) is pre-scanned, (S103), and based on image data by the pre-scan, the present original is judged whether it is full-colored or monochrome-colored (S104). In the case of full color (S105, NO), a first original (previous original) is judged whether it is full-colores or monochrome-colored. In the case of full color, a proper scanning process is performed keeping a low speed mode and image formation is carried out for a specified register-number (S109). In the case the previous mode is monochrome- colored (S11), a system speed is switched to the low speed mode, and thereafter proper scan and subsequently image formation for a specified register-number are carried out (S109).

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 used for a copying machine, a laser printer, a facsimile, and the like, and more particularly to an image forming apparatus suitably used for a full-color copying machine.

[0002]

2. Description of the Related Art Conventionally, a transfer drum type full-color copying machine is generally equipped with an automatic document feeder (ADF) for automatically feeding a document to a platen glass of a copying machine body. In the color selection (ACS) mode, prescanning is performed on a document sent to the platen glass by the ADF, and a document type such as a full-color image or a monochrome (monocolor) image is automatically determined. Is determined. A main scan is performed according to the type of the original, and a toner image is formed on a photosensitive drum based on image information obtained by the main scan, and the toner image is transferred to a recording paper wound around a transfer drum. It is configured as follows.

In a full-color copying machine as described above, when copying a full-color image, the system speed such as the reading speed of the image reader and the rotation speed of the transfer drum must be reduced in order to obtain high image quality. In the case where a mono-color image is to be copied, the system speed can be set to a higher value with emphasis on productivity than image quality.

Therefore, in recent years, in the above-described full-color copying machine, when it is determined that the image is a monocolor image that can be processed at high speed based on the result of the ACS determination, the system speed is switched to the high-speed mode, while the low-speed mode is switched. There has been proposed a system speed switching type in which the system speed is switched to a low-speed mode when it is determined that the image is a full-color image requiring processing.

[0005]

However, in the conventional system speed switching type full-color copying machine, when the system speed is switched, for example, the rotation speed of a polygon motor in an image reader unit is changed, or the image forming unit is changed. In this case, the rotation speed of the drum motor for driving the transfer drum is changed, and when the rotation speed of these motors is switched, the time until the rotation speed (peripheral speed) becomes stable (mode switching time) )Is required. For this reason, when the system speed is switched during continuous copying, for example, when a plurality of originals in which a mono-color original and a full-color original are mixed are continuously copied, the processing time is affected by the mode switching time. In some cases, it may be long, which may lead to a decrease in productivity.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which can solve the above-mentioned problems of the prior art and can further improve productivity while maintaining high image quality.

[0007]

To achieve the above object, the first invention has a low-speed mode for forming an image at a low speed and a high-speed mode for forming an image at a high speed. An image forming apparatus configured to be switchable between a current image and a previous image, wherein the previous image is formed in a low-speed mode, and the current image is formed in a low-speed mode or a high-speed mode. However, if the image is a high-speed processable image that can be formed, whether or not to switch the current mode to the high-speed mode based on the mode switching time required to switch from the low-speed mode to the high-speed mode and image information to be formed after the current image Determining means for determining whether
The gist of the present invention includes a control unit that controls switching between a low-speed mode and a high-speed mode based on information from the determination unit.

In the system speed switching type image forming apparatus, when the system speed mode is switched, a mode switching time is required until the system speed is stabilized. Therefore, for example, when the previous mode is the low-speed mode and only one or several images that can be processed at a high speed are formed, it is better to form the image in the low-speed mode in consideration of the mode switching time. In some cases, the processing time can be reduced as compared with switching and forming an image.

Therefore, in the image forming apparatus of the present invention, switching of the system speed mode is controlled in consideration of the mode switching time and the like. Therefore, when the processing time can be reduced as described above, a current image that can be processed at high speed, such as a monocolor image, can be formed in the low-speed mode, and high productivity can be obtained. .

In the present invention, an image that needs to be formed in a low-speed mode, such as a full-color image, can be formed in a low-speed mode, so that high image quality can be reliably maintained.

On the other hand, in the present invention, a configuration in which the number of current images formed is used as the image information, or a configuration in which the number of continuous high-speed processable images formed after the current image is used as the image information is used. It is preferable to employ it.

That is, when these configurations are employed, the determination at the time of switching the system speed mode can be performed more accurately.

In order to achieve the above object, the second invention has a low-speed mode for forming an image at a low speed and a high-speed mode for forming an image at a high speed, and can be switched between these two modes. In forming the current image and the next image following the previous image, the previous image is formed in the low-speed mode, and the current image can be formed in any of the low-speed mode and the high-speed mode. A high-speed processable image, a determining unit that determines whether to switch the current mode to the high-speed mode based on the type of the next image, and a low-speed mode and a high-speed mode based on information from the determining unit. A gist comprising a control means for controlling the switching is provided.

In the image forming apparatus according to the second aspect of the invention, for example, after the current image is formed by switching from the low-speed mode to the high-speed mode, if it is necessary to switch to the low-speed mode again, the low-speed mode is maintained. In some cases, forming the current image can shorten the processing time compared to once switching to the high-speed mode to form the current image. In such a case, an image that can be processed at high speed remains in the low-speed mode. And high productivity can be obtained.

[0015]

<First Embodiment> FIG. 1 is a schematic diagram showing a full-color copying machine to which an image forming apparatus according to a first embodiment of the present invention is applied. As shown in FIG. 1, the copying machine of this embodiment includes a copying machine main body 10 and an ADF (automatic original feeder) 80 mounted on the copying machine main body 10 as basic components.

The copying machine body 10 includes an image reader section 20.
, A laser beam scanning unit 30, an image forming unit 40, and a paper feeding unit 60.

The image reader unit 20 includes a platen glass 1
9 to read the image of the original placed on
Exposure lamp 21, mirrors 22 to 24, lens 25, solid-state imaging device (CCD) 26, lamp 21, mirror 22
To 24 and the like are provided. When reading the image of the document, the exposure lamp 21 and the mirrors 22 to 24 move along the platen glass 19, while the illumination light emitted from the exposure lamp 21 is reflected on the document surface, and the mirrors 22 to 24 are read. 24, lens 25
The original image is read by the CCD 26 as three primary colors of R (red), G (green), and B (blue).

The electric signal photoelectrically converted by the CCD 26 is stored in a memory 27, and then, in an image signal processor (not shown), each of the colors Y (yellow), M (magenta), C (cyan), and K (black). After being converted into print data corresponding to and appropriately edited, the laser beam scanning unit 3
0 is transferred.

The copying machine can be connected to an external device such as a personal computer, and data from the external device is printed via the memory 27.

The laser beam scanning section 30 modulates a laser diode based on the print data, emits a laser beam from the laser diode, and irradiates a photosensitive drum 41 described later to form an electrostatic latent image. Things.

The image forming section 40 includes a photosensitive drum 41,
It has a transfer drum 51 and a drum motor M2 for rotating these. Around the photoreceptor drum 41, a charging charger 42, a developing unit 43
C, 43M, 43Y, 43K, a residual toner removing cleaner 44, and a residual charge removing eraser 45 are provided. The developing units 43C, 43M, 43Y, and 43K each store a developer containing a toner of each color of CMYK,
Each time an electrostatic latent image of each color is formed on the photosensitive drum 41, the corresponding developing device is driven.

The transfer drum 51 is configured to rotate in the direction of the arrow at the same peripheral speed as the photosensitive drum 41, and is configured to transfer a toner image onto a recording paper wound on the surface. The transfer drum 51 includes a chucking claw (not shown) for chucking the leading end of the recording paper, a separation claw 52 for separating the recording paper, and a cleaner 53 for removing residual toner. Further, the transfer drum 51
Inside and outside, a recording paper suction charger 54, a transfer charger 55, and a charge removal charger 56 are provided.

The paper supply section 60 includes a plurality of paper supply cassettes 61 in which recording papers are set. In the paper feeding section 60, the recording paper fed from any one of the cassettes 61 is transported upward through the transport path 64, and is sent out to the transfer drum 51 at a predetermined timing by a pair of timing rollers 65, and chucked. Is done.

In this copying machine, when performing full-color copying, images of respective colors of CMYK are sequentially formed on the photosensitive drum 41, and the toner images are chucked on the transfer drum 51 by discharge from the transfer charger 55, respectively. Is transferred onto the recording paper and is superimposed. Note that the transfer drum 51 rotates according to the number of times of color superposition.

When the images of the respective CMYK colors are superimposed on the recording paper, the recording paper is discharged by the discharge from the charger 56, and the recording paper is fed to the fixing device 71 by the action of the separation claw 52 to fix the toner. After the discharge, the duplex sorter 100
Sent to.

In the present embodiment, full-color copying can be performed by superimposing three colors in addition to superimposing four colors including black toner. Or,
It is possible to create a monochrome copy using only black toner, a monochromatic monocolor copy by specifying a color, and a color copy using two colors.

The ADF 80 feeds / conveys the originals set on the original stacker 81 one by one onto the original platen glass 19, and discharges the originals onto the tray 95 after the reading of the original image by the image reader unit 20 is completed. I do. That is,
The ADF 80 includes a paper feed roller 82 for feeding a document from a stacker 81, a separating roller 83, and a registration roller 8.
The original is set in the stacker 81, and is sequentially fed from a lowermost original of the originals set in the stacker 81 by the paper feed roller 82, and is fed onto the original glass 19 through the rollers 83 and 84. At a position corresponding to the upper surface of the platen glass 19, a transport belt 85 is installed rotatably in the forward and reverse directions. By rotating forward, the document fed from the registration roller 84 is placed on the platen 19 by the document scale 18. Is set on the basis of.

Also, on the side of the ADF 80, a document discharge /
A reversing roller 91 and a discharge roller 92 are provided.

In the case of a single-sided original (single-sided original mode), when the reading of the image is completed, the conveying belt 85 is rotated forward, and the single-sided original is conveyed around the roller 91 and is discharged from the discharge roller 92 to the tray. The paper is discharged onto the upper surface 95 with the image holding surface facing upward.

In the case of a double-sided original (double-sided original mode), the double-sided original sent from the registration roller 84 onto the original platen glass 19 passes through the original platen glass 19 as it is, and is around the discharge / reverse roller 91. Is turned around once. At the same time, the transport belt 85 is rotated in the reverse direction, and the inverted document is transported so that the trailing edge of the document matches the document scale 18. At this point, an image is read on the back side of the original.
Turn around and flip. The original is set on the original platen glass 19 with the front surface facing downward, and an image is read from the front surface of the original. When the reading is completed, the original is discharged onto a tray 95 through a discharge / reversal roller 91 and a discharge roller 92 with its surface facing upward.

The ADF 80 is rotatable up and down with the back of the copier main body 10 as a fulcrum. The document table glass 19 is opened so that an operator can manually set a document.

The duplex sorter 100 is provided in the recording paper discharge section 121 of the copying machine body 10.
The sorter 100 is provided with a plurality of bins 101. In the non-sort mode, the recording paper sent from the recording paper discharge unit 121 of the copier main body 10 receives the uppermost bin 10
1 and in the sort mode, they are sorted into bins 101 of each stage.

The copying machine according to the present embodiment has the above-described configuration and is further configured to be switchable between a low-speed mode and a high-speed mode. In the low-speed mode, the system speed decreases, that is, the rotation speed of the polygon motor M1 in the image reader unit 20 and the rotation speed of the drum motor M2 that rotates the transfer drum 51 of the image forming unit 40 decrease, and high image quality can be obtained. In the high-speed mode, the system speed is increased, that is, the rotation speeds of the motors M1 and M2 are increased, and the productivity can be increased. In this copying machine, when copying a full-color image, it is necessary to perform in a low-speed mode in order to obtain high image quality, and when copying an image in which the image quality is not so important, such as a monocolor image such as a monochrome image. Can be copied in both the high-speed mode and the low-speed mode.

The copying machine according to the present embodiment has a system speed mode determining means for determining whether processing is performed in the low speed mode or the high speed mode in accordance with a determination method described later in detail, System speed control means for controlling switching between the low speed mode and the high speed mode based on the information, ADF control means for controlling the drive of the ADF 80, IR control means for controlling the drive of the image reader unit 20, Image processing control means for processing image information taken in by the reader unit 20 in accordance with a copy sequence, a copy mode, and the like; panel control means for controlling key input processing and display of an operation panel; a photosensitive drum 41; Control unit for controlling the paper feed unit 60 and its peripheral devices, a sorter control unit for controlling the sorter 100, etc. Includes various control means further includes a system controller for centrally controlling each control unit thereof.

In the copying machine according to the present embodiment,
When continuously copying a plurality of originals in which a full-color original and a mono-color original are mixed, the following operation is performed.

That is, when a plurality of originals are set on the stacker 81 of the ADF 80, desired copy conditions such as the number of originals are set via the operation panel, and then the start button is pressed to start copy processing. As shown in step S101 of FIG. 2, copying of the first document is started.

In the first copy, as shown in a subroutine of FIG.
The first document is conveyed onto the platen glass 19 (step S11), and the image reader 20
In step S12, a pre-scan is performed (step S12), and the type of the document, that is, a full-color image or a mono-color image is determined by the ACS function based on the image data (step S13).

If the original is full color in step S14, the system speed mode is set to the low speed mode (step S17). Then step S
As shown in FIG. 16, after the main scan is performed and an electrostatic latent image and a toner image are formed based on the image data, each toner image is transferred to recording paper. Further, this image forming process is performed for a predetermined number of copies, and the number of recording sheets on which an image has been formed is sequentially sent from the recording paper discharge unit 121 to the bin 101 of the sorter 100.

If the original is monochrome in step S14, after the system speed mode is set to the high-speed mode (step S15), a main scan is performed, and image forming processes for the number of copies are performed. (Step S1
6) The recording paper on which the image is formed is discharged from the discharge unit 121.

When the first document is copied in this manner, the first document is discharged onto the tray 95 by the ADF 80 and the second document (current) as shown in step S102 of FIG. The original is conveyed onto the original glass 19 by the ADF 80, and the original is pre-scanned (step S103). Then, based on the image data obtained by the prescan, as shown in step S104, the ACS function determines whether the current document is full color or monocolor.

If the current document is full color (step S105, NO), it is determined whether the previous mode is the low speed mode, as shown in step S111, that is, 1
It is determined whether the first document (previous document) is a full-color monocolor image, and the color (step S111, YE
In the case of S), the main scan processing is performed in the low-speed mode without switching the system speed, and after a predetermined number of images have been formed (step S109), the number of images formed has been changed. Of recording paper is discharged from the discharge unit 121.

In step S111, if the previous mode is monocolor, as shown in step S112, after the system speed is switched to the low speed mode, the main scan is performed and an image is formed for a predetermined number of times ( In step S109, the recording paper is discharged from the discharge unit 121.

On the other hand, if the current color mode is monocolor in step S105, whether or not the previous mode is low speed mode is determined in step S106, that is, whether the first document is full color (low speed mode) or not. It is determined whether the mode is the color mode (high-speed mode). If the mode is the mono-color mode (step S106, NO), the main scan process and the image forming process are performed in the high-speed mode without switching the system speed (step S106). S109).

If the previous mode is the low-speed mode in step S106, it is determined in step S107 whether or not the set number is larger than a predetermined value N.

Here, the predetermined value N is obtained as follows. That is, the time required for copying a monocolor original in the high-speed mode is "T1", the time required for copying a monocolor original in the low-speed mode is "T2", and the system speed mode is switched from the low-speed mode to the high-speed mode. Mode switching time required for the polygon motor M1,
When the drum motor M2 switches from the low-speed rotation in the low-speed mode to the high-speed rotation in the high-speed mode and the time until the rotation speed stabilizes is "T3", N * T1 +
The predetermined value N is obtained based on the relational expression of T3 = N × T2.

In other words, in step S107,
The fact that the set number is larger than the predetermined value N means that the time required for the copy process is shorter when copying to the set number after switching to the high-speed mode than when copying for the set number in the low-speed mode. The fact that the set number is smaller than the predetermined value N means that copying in the set number in the low-speed mode is necessary for the copy processing than in copying the set number after switching to the high-speed mode. But the time is short.

Therefore, if the number is smaller than the predetermined value N in step S107, the main scan process and the image forming process are performed in the low speed mode without switching the system speed (S109). The recording paper is ejected.

If the number is larger than the predetermined value N in step S107, the system speed is switched from the low-speed mode to the high-speed mode in step S108. Is performed (S109), and the recording paper is discharged.

After the copying of the second document is completed, it is determined in step S110 whether or not there is a next document. If there is no next document, the current document is discharged to the tray 95 and copied. When the process is completed and there is a next document, the process returns to step S102, where the current document is discharged to the tray 95 by the ADF 80, and the next document is conveyed to the platen glass 19, and the same processing ( Steps S103 to S112) are performed.

Then, all the originals set on the ADF 80 are copied, and the copy processing is completed.

As described above, according to the copying machine of the present embodiment, when the previous mode is a low-speed mode for full-color copying and a monocolor original that can be processed in the high-speed mode is copied, the mode switching time and In consideration of the above, if the mode switching is not performed, the processing time can be reduced. If the mode switching can reduce the processing time, the mode switching is performed. Therefore, productivity can be further improved. In addition, a high-quality copy, such as a full-color original, is performed in a low-speed mode, so that a high-quality full-color image can be reliably maintained.

<Second Embodiment> In the first embodiment, whether or not to switch the system speed mode is determined based on the number. The copying machine according to the second embodiment is described. In, the manuscript before being processed continuously,
This determines whether or not to switch the system speed mode based on the image information of the current document and the next document, and corresponds to the invention of claim 4 of the present application.

In the copying machine according to the second embodiment,
Two originals can be placed on the original platen glass 19, and the two originals can be read at once by the image reader unit 20.

In this copying machine, when copying a plurality of originals in which a full-color original and a mono-color original are mixed one by one (at a setting number of 1), the following operation is performed.

First, the original is set on the stacker 81 of the ADF 80 and the start button is pressed.
As shown at 201, the first copy is performed. This one
The copy operation of the sheet is almost the same as the operation shown in FIG. That is, the first document is transported to the set position on the platen glass 19, and the second document is transported to a position on the platen glass 19 that is aligned with the first document (step S11). Subsequently, a pre-scan is performed on each document in the image reader unit 20 (step S12), and based on the image data, the type of each document, that is, a full-color image or a mono-color image is determined by the ACS function. (Step S13).

If the first document is a color document (step S14, NO), the system speed mode is set to the low speed mode (step S17), the main scan is performed, and the electrostatic latent image and The formation of toner images, the transfer of each toner image to recording paper, and the like (image forming processing) are performed (step S16), and the toner images are sent from the recording paper discharge unit 121 to the bin 101 of the sorter 100.

If the first original is monocolor (step S14, YES), the system speed mode is set to the high speed mode (step S15), and the main scan process and the image forming process are performed (step S16). ).

When the first copy is completed in this way, the first document (previous document) is discharged onto the tray 95 by the ADF 80 and the second document (current document), as shown in step S202 of FIG. ) Is conveyed to the set position of the platen glass 19, and the third document (next document) is conveyed on the platen glass 19 to a position aligned with the second document.

Subsequently, a prescan is performed on the third original (next original) (step S203), and the image type is determined (step S204).

Next, if the second original (current original) is a full-color original (step S205, NO), it is determined in step S211 whether or not the previous mode is the low-speed mode. In step S20, the main scan process and the image forming process are performed in the low speed mode without switching the system speed mode.
9) The recording paper on which the image is formed is discharged from the discharge unit 121.

If the previous mode is the high-speed mode in step S211, step S212
After the system speed mode is switched to the low speed mode, the main scanning process and the image forming process are performed (step S209), and the recording paper is discharged.

On the other hand, if the current original is a monocolor original in step S205, the system speed mode of the previous mode is determined in step S206.
If the previous mode is not the low-speed mode, that is, if the previous mode is the high-speed mode (step S206, NO), the main scan process and the image forming process are performed without switching the system speed mode and keeping the high-speed mode (step S206). S2
09), the recording paper is discharged.

If the previous mode is the low speed mode in step S206 (step S206, YES), the color mode of the next original is determined in step S207, and if the next original is not a monocolor original, that is, the next original is a full color original. If there is (step S207,
NO), the main scanning process and the image forming process are performed without switching the system speed mode and in the low speed mode (step S209), and the recording paper is discharged.

If the next original is a monocolor original in step S207, that is, if the next original is an image that can be processed in the high-speed mode following the current original,
As shown in step S208, after the system speed mode is switched to the high speed mode, the main scan process and the image forming process are performed (step S209), and the recording paper is discharged.

After the copying of the current document is completed, the same processing as described above is performed on the third document.

Such processing is repeatedly and continuously performed, and it is determined in step S210 whether or not there is a next original. If there is no next original, the current original is discharged to the tray 95, and the copy processing is completed. If there is a next original, the same processing as described above is performed.

Thus, all the originals set on the ADF 80 are copied, and the copy processing is completed.

As described above, according to the present embodiment, when the previous mode is the low-speed mode and a high-speed monocolor original is copied, the next original is a high-speed monocolor original. In other words, when a document that can be processed at high speed continues after the current document and the next document, the system speed mode is switched to the high speed mode and copying is performed.
As described above, the system speed mode is switched only when necessary in consideration of the mode switching time, so that the productivity can be further improved. In addition, a high-quality copy, such as a full-color original, is performed in a low-speed mode, so that a high-quality full-color image can be reliably maintained.

In this embodiment, the set number is “1”.
Has been described, but is not limited thereto.
In a copying machine in which an RDH (Recycle Document Handler) is used as F, the same processing as described above can be performed even when the number of copies is plural.

<Third Embodiment> A copying machine according to a third embodiment determines whether or not to switch the system speed mode based on the number of continuously formed images that can be processed at high speed such as a monocolor image. This corresponds to the third aspect of the present invention.

That is, the copying machine according to the third embodiment comprises:
The image information of a plurality of originals set in the ADF 80 is all read, stored in a memory, and an image is formed based on the stored data.
It is configured to print one sheet at a time in the order of the originals, and to repeat the printing for the set number.

In this copying machine, when copying a plurality of originals in which a full-color original and a mono-color original are mixed, the following operation is performed.

First, as shown in step S301 of FIG.
The document is conveyed upward, and the image of the document is read and stored in the memory (steps S302 and S303).

Next, the first document is discharged to the tray 95, and the second document is conveyed onto the platen glass 19 (step S304 YES, S305), and the image of the second document is read. Is stored in the memory.

After the image information of all the originals is read and stored in the memory (step S304, N
O), the reading process is completed.

On the other hand, after the image reading process of FIG. 5 is completed,
Alternatively, the printing process is executed with a delay from the process.

First, as shown in step S401 of FIG. 6, print processing corresponding to the first document is performed.
That is, the image type of the first document is determined. In the case of a full-color image, the system speed mode is set to the low-speed mode, and in the case of a mono-color image, the high-speed mode is set. Similarly to the second embodiment, an image is formed on a recording sheet and discharged from the discharge unit 121.

Subsequently, as shown in step S402 of FIG. 6, it is determined whether or not the second document (current document) is a mono-color image. If the second document is not a mono-color image, that is, if it is a full-color image, In step S408,
It is determined whether or not the previous mode is the low-speed mode. If the previous mode is the low-speed mode (step S408, YES), the image forming process is performed in the low-speed mode without switching the system speed mode, as shown in step S406. Then, the recording paper is discharged.

If the previous mode is the high-speed mode in step S408, the system speed mode is switched to the low-speed mode (step S409), image forming processing is performed (step S406), and the recording paper is discharged. .

On the other hand, if the current document is a mono-color document in step S402, then in step S403
It is determined whether or not the previous mode is the low-speed mode. If the previous mode is not the low-speed mode, that is, in the case of the high-speed mode for forming a mono-color image, the system speed mode is not switched.
The image forming process is performed in the high-speed mode (step S406), and the recording paper is discharged.

If the previous mode is the high-speed mode in step S403, the process proceeds to step S404.
It is determined whether or not the number of continuously formed monocolor images (high-speed processable images) after the current document is larger than a predetermined value N.

Here, the number of continuous monocolor image formations (the number of continuous monocolor images) is, for example, one, when the current document is a monocolor image, the next document is a monocolor image, and the next document is a full color image. Is "2", which is the number of continuous monocolor images formed in the subsequent images including the current document.

The predetermined value N is obtained in the same manner as in the first embodiment. That is, the required time for forming an image in the high-speed mode is “T1”, the required time for forming an image in the low-speed mode is “T2”, and the mode switching time required to switch the system speed mode from the low-speed mode to the high-speed mode. Is “T3”, N × T1 + T3 = N × T
The predetermined value N is obtained based on the relational expression (2).

In other words, in step S404,
The fact that the continuous number of monocolors is larger than the predetermined value N means that switching to the high-speed mode and printing the continuous number of monocolors is more effective than printing the continuous number of monocolors in the low-speed mode. The time can be shortened, and the fact that the number of continuous mono-colors is smaller than the predetermined value N means that printing in the continuous number of mono-colors in the low-speed mode can be performed by switching to the high-speed mode and the continuous printing of the mono-colors. This means that the processing time is shorter than when printing for several minutes.

Therefore, in step S404, if the continuous number of monocolors is smaller than the predetermined value N, the image forming process is performed in the low-speed mode without switching the system speed (S406), and the recording paper is discharged. Is discharged. Also, in step S404, when the continuous number of monocolors is smaller than the predetermined value N, in step S405,
After the system speed is switched from the low speed mode to the high speed mode, an image forming process is performed (S406), and the recording paper is discharged.

After the image corresponding to the second document is thus formed, it is determined in step S407 whether there is a next image. If there is no next image, the printing process is completed, and the next image is printed. If so, an image is formed by the same processing as described above.

As a result, all the originals set on the ADF 80 are copied.

As described above, according to the copying machine of the present embodiment, when the previous mode is a low-speed mode for full-color copying and a monocolor image that can be processed in the high-speed mode is printed, the mode switching time and the current Considering the number of continuous mono colors including originals, if it is more efficient not to switch the mode, the mode switching is not performed.If the mode switching is more productive, Since the mode is switched, the productivity can be further improved. In addition, a high-quality image, such as a full-color image, is copied in a low-speed mode, so that a high-quality image can be reliably maintained in a full-color image.

In each of the above embodiments, the case where the image forming apparatus of the present invention is applied to a copying machine has been described. However, the present invention is not limited to this. And the like.

For example, as shown in FIG. 7, a plurality of personal computers 1 to 3 communicate with a shared network printer 4 or a digital (full color) copying machine 5 such as the above-described embodiment which can be used as a shared network printer. The present invention can also be applied to a network system that is connected by the line 6 and prints out print data output from a personal computer via a predetermined printer. In such a network system, as in the above embodiment, it is determined whether or not to switch the system speed mode based on the mode switching time required for switching the system speed mode and image information after the current image. The mode may be switched so that the processing time is reduced.

In the first embodiment, it is determined whether or not to switch the system speed mode based on the mode switching time and the number of the current document. In the second embodiment, the next document is determined. In the third embodiment, it is determined whether or not to switch the system speed mode based on the type of the original. In the third embodiment, the system speed mode is determined based on the mode switching time and the number of successively formed monocolor images after the current original. It is determined whether or not to switch. However, the present invention is not limited to using the determination methods of the first to third embodiments individually, and these determination methods are appropriately used in combination. It may be used.

[0092]

As described above, according to the image forming apparatus of the present invention, when forming the current image, if the previous mode is the low-speed mode and the current image is a high-speed processable image,
Since the switching of the system speed mode is controlled based on the system speed mode switching time and the image information after the current image, even if the current image is a high-speed processable image, the mode switching time is considered. If the processing time can be reduced by forming an image in the low-speed mode, an image capable of high-speed processing can be formed in the low-speed mode, so that productivity can be further improved. Furthermore, an image that needs to be formed in the low-speed mode, such as a full-color image, can be surely formed in the low-speed mode, so that there is an effect that high image quality can be maintained.

In the present invention, when the number of current images formed or the number of continuously formed images that can be processed at high speed after the current image is used as the image information, the above effects can be obtained more reliably. There is an advantage.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating an operation of the full-color copying machine according to the first embodiment.

FIG. 3 is a diagram illustrating a full-color copying machine according to the first embodiment;
9 is a flowchart illustrating a sheet copy operation.

FIG. 4 is a flowchart illustrating an operation of the full-color copying machine according to the second embodiment.

FIG. 5 is a flowchart illustrating an original reading operation in a full-color copying machine according to a third embodiment.

FIG. 6 is a flowchart illustrating a printing operation in a full-color copying machine according to a third embodiment.

FIG. 7 is a block diagram illustrating a network system to which an image forming apparatus according to a modification of the invention is applied.

[Explanation of symbols]

 4, 5 printer 40 image forming unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Hino 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Kentaro Nagatani Azuchi-cho, Chuo-ku, Osaka-shi, Osaka 2-3-1-3 Osaka International Building Minolta Co., Ltd. (72) Inventor Yoshiaki Takano 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2H027 DB02 FA01 FA02 FA28 FA30 FB05 FB11 FB19 2H030 AD07 AD16 9A001 HH34 JJ35 KK42

Claims (4)

[Claims] 1. An image forming apparatus having a low-speed mode for forming an image at a low speed and a high-speed mode for forming an image at a high speed, wherein the image forming apparatus is configured to be freely switchable between these two modes. In the subsequent formation of the current image, if the previous image is formed in the low-speed mode and the current image is a high-speed processable image that can be formed in both the low-speed mode and the high-speed mode, the low-speed mode is changed to the high-speed mode. Determining means for determining whether or not to switch the current mode to the high-speed mode based on the mode switching time required for switching and image information to be formed after the current image; An image forming apparatus comprising: a control unit that controls switching between a mode and a high-speed mode. 2. The image forming apparatus according to claim 1, wherein the number of current images formed is used as the image information. 3. The image forming apparatus according to claim 1, wherein the number of continuously formed high-speed processable images formed after the current image is used as the image information. 4. An image forming apparatus having a low-speed mode for forming an image at a low speed and a high-speed mode for forming an image at a high speed, wherein the image forming apparatus is configured to be switchable between these two modes. When the current image and the next image are successively formed, if the previous image is formed in the low-speed mode and the current image is a high-speed processable image that can be formed in any of the low-speed mode and the high-speed mode, the next image is formed. An image forming apparatus comprising: a determination unit configured to determine whether to switch a current mode to a high-speed mode based on a type; and a control unit configured to control switching between a low-speed mode and a high-speed mode based on information from the determination unit. .