JPH1083104A - Image forming device and method for controlling it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform optimum both-side recording corresponding to the color number of recording or the size and the direction of a recording medium. SOLUTION: In the case of recording the full color images or two pages on both sides of one recording medium, the images of a second page are firstly formed on the recording medium and are fixed, and the recording medium is carried by an inversion unit. During this processing, the images equivalent to a first page are formed on an inter-mediate transfer body. Since the toner images of totally four colors are formed on the intermediate transfer body, the inverted recording medium is carried if in the processing, so that the image- forming of the toner image of a fourth page for transfer to a nest recording medium is started as well as performing transfer to the recording medium inverted and ejecting it, and the process is repeated thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus for a copying machine or a printer, for example, in which an input image is formed on an intermediate transfer member and then secondary transferred to a transfer material. The present invention relates to an image forming apparatus that performs output and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image based on input image information data is formed on a photosensitive drum, developed by attaching toner to the image, and then transferred onto an intermediate transfer member. There is an apparatus that secondary-transfers the toner image transferred on the intermediate transfer member to a recording medium.

When an image is formed on both sides of a recording medium in an apparatus having such a configuration, in order to output the image with the front side up, the image is first transferred to the back side of the both sides in the above-described sequence and fixed. After that, the recording medium is reversed by a mechanism called a reversing unit, which is again image-formed on the front surface in the above-described sequence, and recording is performed on both sides.

On the other hand, yellow (Y), magenta (M),
There is also an apparatus that obtains a full color by superimposing each component of cyan (C) and black (Bk) and performing secondary transfer. In general, even in a full-color image forming apparatus, an image can be formed in monochrome (for example, Bk single color), so that an image is formed on both sides according to the above sequence.

[0005]

However, double-side recording in this type of apparatus has been performed uniformly in the same sequence or timing, and there is a problem in efficient image formation, and there is still room for improvement. was there.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an image forming apparatus for performing high-speed and optimum double-sided recording by changing an image forming sequence, and a control method and a control method thereof. Is intended to provide a recording medium in which is stored. Further, the present invention provides a control device which can notify the host computer of an image forming time when an image sequence is determined.

In order to solve this problem, for example, an image forming apparatus of the present invention has the following configuration. That is.

An image forming apparatus for sequentially forming a plurality of images on a recording medium, comprising: an intermediate transfer means capable of holding an image corresponding to the image; and transferring the image on the intermediate transfer means to the recording medium. A transfer unit, a reversing unit for reversing the recording medium to form an image on the back surface of the recording medium on which the image is formed, and a method for sequentially forming the plurality of images on both surfaces of the recording medium using the reversing unit. And control means for controlling image formation of the plurality of images in accordance with image formation conditions.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

[Description of Configuration of Control System of Image Forming Apparatus] FIG. 1 is a block diagram of a control system of an image forming apparatus (laser beam printer) according to the embodiment.

In FIG. 1, reference numeral 1 denotes a CPU that controls the entire apparatus, and 2 denotes a ROM that stores an operation processing procedure (program) of the CPU 1. Reference numeral 3 denotes a RAM used as a work area of the CPU, and reference numeral 4 denotes an operation panel. Reference numeral 5 denotes an interface for receiving data from the host computer 8, and reference numeral 6 denotes an image memory for developing bitmap data to be printed. In the present embodiment, there is a capacity that allows full-color image data up to A3 size to be developed at the resolution of the engine that actually forms the image. Therefore, in the case of A4 size, full-color image data for two pages can be stored, and in the case of A4 size monochrome image data, eight pages can be stored. The bitmap data developed in the image memory 6 is PWM-modulated, for example, and an image is formed by an image forming unit 7 described later.

[Overall Description of Image Forming Apparatus] FIG. 2 shows a cross-sectional structure of the image forming apparatus in the embodiment.

As shown in the figure, a fixed black developing device 21B
Then, the color image developed by the developing unit 23 equipped with three rotatable color developing devices and multiplex-transferred onto the intermediate transfer body 9 is further transferred to the transfer material 2 fed from the feeding unit. A color image is formed. Then, the transfer material 2 is conveyed to the fixing unit 25 to fix the color image on the transfer material 2, and is discharged by a discharge roller 37 on the upper surface of the apparatus.
Discharge to

The rotatable color developing device and the fixed black developing device are configured to be individually detachable from the printer main body.

Exposure to the image forming section is performed by the scanner section 30.
Sent from That is, when an image signal is given to the laser diode, the laser diode irradiates the polygon mirror 31 with image light corresponding to the image signal. The polygon mirror 31 is rotated at a high speed by a scanner motor, and the image light reflected by the polygon mirror 31 is rotated at a constant speed via the imaging lens 32 and the reflection mirror 33.
5 is selectively exposed.

Next, the configuration of each section of the image forming section will be sequentially described in detail.

<Image holding unit> Drum unit 13
Is integrally formed with a container 14 of the cleaning device which also serves as a holder for the image holding member (photosensitive drum) 15 and the image holding member 15. The drum unit 13 is detachably supported with respect to the printer main body. The unit can be easily replaced according to the life of the body 15. The image holding member 15 according to the present embodiment is configured by applying an organic photoconductor layer to the outside of an aluminum cylinder having a diameter of about 60 mm,
It is rotatably supported by the container 14 of the cleaning device which also serves as a holder for the image holder 15. A cleaner blade 16 and a primary charging means 17 are arranged on the periphery of the image holder 15, and the driving force of a drive motor (not shown) is transmitted to one end on the rear side in the figure, so that the image holder 15 is imaged. It is rotated counterclockwise in the figure according to the forming operation.

<Charging Means> The charging means 17 employs a contact charging method, in which a conductive roller is brought into contact with the image carrier 15 and a voltage is applied to the conductive roller to thereby charge the image carrier. 15 to uniformly charge the surface.

<Cleaning Unit> The cleaning unit cleans the toner remaining on the image holding member 15 after the toner visualized on the image holding member 15 is transferred to the intermediate transfer member 9 by the developing unit. The waste toner that has been cleaned is stored in the cleaner container 14. The amount of waste toner stored in the container 14 does not fill the container 14 earlier than the life of the image holder, and therefore, the cleaner container 14 is simultaneously replaced when the life of the image holder 15 is replaced.

<Developing Unit> The developing unit includes three rotary developing units 20Y, 20M, 20M that enable development of each color of yellow, magenta, and cyan in order to visualize the latent image.
C and one black developing unit 21B.

The black developing device 21B is a fixed developing device as described above, and the sleeve 21BS is arranged at a position facing the image holding member 15 with a small interval from the image holding member 15, and Then, a visible image is formed on the layer 15 with black toner.

The black developing device 21B feeds the toner in the container by a feeding mechanism, applies a thin layer of toner to the outer periphery of the sleeve 21BS rotating clockwise in the drawing by an application blade 21BB pressed against the outer periphery of the sleeve 21BS, and Charge (frictional electrification). Also, by applying a developing bias to the sleeve 21BS,
The toner development is performed on the image holder 15 in accordance with the latent image.

Three rotary developing units 20Y, 20M, 20C
Are detachably held by a developing rotary 23 which rotates about a shaft 22. When forming an image, the shaft 22 is held in a state where each developing device is held by the developing rotary 23.
, The predetermined developing device is stopped at a position facing the image holding member 15, and the developing sleeve is further moved to the image holding member 15.
Are positioned so as to face each other with a small interval (about 300 μm), and then a visible image is formed on the image holding member 15. At the time of forming a color image, the developing rotary 23 rotates for each rotation of the intermediate transfer member 9, and a developing process is performed in the order of a yellow developing device 20 </ b> Y, a magenta developing device 20 </ b> M, a cyan developing device 20 </ b> C, and then a black developing device 20 </ b> B. Rotates four times to sequentially form visible images with yellow, magenta, cyan, and black toners, thereby forming a full-color visible image on the intermediate transfer member.

FIG. 2 shows a state in which the yellow rotary developing unit 20Y is positioned at a position facing the image holding unit and is stationary. The rotary developing device 20Y feeds the toner in the container to the coating roller 20YR by a feeding mechanism, and the coating roller 20YR that rotates clockwise in the drawing and the outer circumference of the sleeve 20YS that rotates clockwise by the blade 20YB that is pressed against the outer circumference of the sleeve 20YS. A thin layer of toner on the surface and apply charge to the toner (frictional charging)
I do. By applying a developing bias to the sleeve 20YS facing the image holding member 15 on which the latent image is formed, toner development is performed on the image holding member 15 in accordance with the latent image. In the magenta developing device 20M and the cyan developing device 20C, toner development is performed by the same mechanism as described above.

Each of the rotary developing devices 20Y, 20M, 20C
Each of the sleeves is connected to a high-voltage power supply for each color development and a drive provided in the printer body when each developing unit is rotated to the development position, and a voltage is selectively applied to each color development sequentially and the drive is connected. Is done.

<Intermediate Transfer Body> The intermediate transfer body 9 rotates clockwise to receive four multiple transfers from the image bearing member during the color image forming operation. The transfer material 2 is sandwiched and conveyed by the transfer roller 10 to which the image is applied, so that the toner images of the respective colors on the intermediate transfer material are simultaneously multiplex-transferred onto the transfer material 2.

The intermediate transfer member 9 according to this embodiment has a diameter of 1
The outer circumference of an 80 mm aluminum cylinder 12 is covered with an elastic layer 11 of medium resistance sponge, medium resistance rubber or the like. The intermediate transfer member 9 is driven by a gear (not shown) which is rotatably supported and integrally fixed, and rotates.

Since the diameter of the intermediate transfer member 9 is as described above, at least two A4 size toner images can be formed.

<Sheet Feeding Unit> The sheet feeding unit transfers the transfer material 2 to the image forming unit.
And a plurality of transfer materials 2 are stored in a cassette 1.
a or 1b. Paper feed rollers 3a and 3b for taking in only one transfer material are in contact with each cassette. The transfer material taken in by the paper feed roller 3a (or 3b) is fed to the feed rollers 4a, 5a (or 4b, 5b).
The sheet is conveyed along the paper feed guide 6 while being sandwiched in b), and conveyed to the registration roller 8 by the common conveying roller 7. During the image forming operation, the registration roller 8 performs, in a predetermined sequence, a non-rotating operation for keeping the transfer material 2 stationary and a rotating operation for conveying the transfer material 2 toward the intermediate transfer member. Then, the position of the image and the transfer material 2 in the transfer step is adjusted.

The transport roller 7 also takes in the inverted transfer material from a reversing unit 41 to be described later and supplies it to the registration roller 8.

<Transfer Section> The transfer section comprises a swingable transfer roller 10. The transfer roller 10 has a metal shaft wound around a medium-resistance foamed elastic body, and can be moved up and down in the figure and is driven. While forming the four-color toner image on the intermediate transfer member 9, that is, while the intermediate transfer member 9 rotates a plurality of times, the transfer roller 10 is positioned below as shown by a solid line in the drawing so as not to disturb the image. It is separated from the intermediate transfer member 9. After the formation of the four color toner images on the intermediate transfer member 9, the transfer material 2
The transfer roller 10 is pressed by a cam member (not shown) at an upper position shown by a thin line in the drawing, that is, the intermediate transfer body 9 via the transfer material 2 at a predetermined pressure in accordance with the timing of transferring the color image to the intermediate transfer body 9. At this time, the transfer roller 10
Is applied, and the toner image on the intermediate transfer member 9 is transferred to the transfer material 2. Here, since the intermediate transfer body 9 is driven with respect to the transfer roller 10, the transfer material 2 sandwiched between the two is transferred at a predetermined speed to the left in the figure at the same time as the transfer process is performed. It is sent to the fixing section, which is the process.

<Fixing Unit> The fixing unit 25 includes the developing unit 2
The toner image formed on the transfer material 2 is fixed on the transfer material 2 via the intermediate transfer body 9 with the toner image formed by the toners 0 and 21. As shown in FIG. The roller 26 is composed of a roller 26 and a pressure roller 27 for pressing the transfer material 2 against the fixing roller 26. Each roller is a hollow roller and has heaters 28 and 29 therein, and is driven to rotate, and conveys the transfer material 2 at the same time. It is configured as follows.

That is, the transfer material 2 holding the toner image is conveyed by the fixing roller 26 and the pressure roller 27, and the toner is fixed to the transfer material 2 by applying heat and pressure.

<Reversing Unit> The reversing unit is a mechanism for reversing the transfer material in order to form an image on the other side of the transfer material having an image fixed on one side.

The transfer material fixed as described above is discharged onto the discharge tray 37 by driving the transport rollers 34 and 35 and the discharge roller 36 when the processing on the transfer material is completed. However, after the fixed transfer material is conveyed by the conveying rollers 34 and 35 in a direction in which the transfer material is discharged to some extent, the conveying rollers 34 and 35 are rotated in reverse. At this time, the illustrated flapper 40 is moved upward (turned clockwise) to be carried into the reverse conveyance path 41.
Thereafter, the sheet is again conveyed to the conveying roller 7 by the reversing path conveying rollers 42 and 43, and is conveyed to the position of the registration roller 8.

[Image Forming Sequence] Next, a sequence in the case where an image is formed by the above-configured apparatus will be described.

For the sake of simplicity, the time required for transferring the transfer material that has been inverted to the registration roller position in the embodiment is longer than the period during which the secondary transfer is performed. , Do not exceed twice that.

<Description of Monochrome Double-sided Printing> First, a case where monochrome double-sided recording (here, black single color) is performed first, in the outer circumferential direction of the intermediate transfer body 9 (perpendicular to the rotation axis of the intermediate transfer). A case where an A4 size toner image in the longitudinal direction is generated and recorded on the front and back sides will be described. In this case, two toner images cannot be transferred to the intermediate transfer member 9 (since the peripheral length of the intermediate transfer member is short to transfer two toner images in the longitudinal direction of A4 size). ,
One sheet of the toner image is transferred, and the transferred toner image is transferred onto a recording sheet as a transfer material.

The operation will be described below with reference to the operation sequence shown in FIG.

First, in the first stage, an electrostatic latent image for black of the second page (the image on the back of the first page) to be recorded is formed on the image holding member 15, and this is formed into a black developing unit 21B. And temporarily transferred to the intermediate transfer member 9. At this time, the transfer material (A4) is transported from the cassette to the registration roller 8, and is kept in a standby state. Then, the black toner image formed on the intermediate transfer body 9 is secondarily transferred to the transfer material, and is fixed by the fixing device 25. The fixed transfer material is conveyed again to the registration roller 8 by the operation of the reversing unit as described above.

During this reversing process, the development, transfer and fixing of the fourth page (the image on the back of the second sheet) are performed on the next transfer material so that the time during this period is not meaningless. Is referred to as an image forming process).

Therefore, when the second page is recorded on the first transfer material, the above image forming process is made to run idle for one time.
At the time of the second image forming process, the image forming process of the fourth page is performed on the second transfer material.

When the image forming process for the fourth page on the second transfer material is completed in this way, the image forming process for the first page (the image of the first sheet) on the transfer material that has been subjected to the reversal process is performed. This time, it is conveyed and discharged toward the paper discharge tray 37.

Thereafter, the image forming process is executed according to the above sequence without interruption. However, in the case of recording on both sides of the last transfer material, since the recording process on the next transfer material is not performed, the image forming process is skipped only once.

By performing double-sided recording as described above,
The output tray 37 is stacked in the page number order. The general sequence is shown in the lower part of FIG.

<Description of Full-Color Image Double-Sided Recording, Part 1>
As described above, in the case of double-sided printing in monochrome monochrome, it takes time to invert the image by the reversing unit and to transport the image. Therefore, it is necessary to store at least four pages of image data. This is because, according to the sequence of FIG. 3, for example, after recording the sixth page, it is necessary to record the image of the third page. When such a sequence is applied to a full-color image, the image memory requires an enormous capacity. This is because forming three (four) images of Y, M, and C (Bk) to form one page of a full-color image requires three (4) times as much data as monochrome.

Therefore, in this embodiment, a series of sequences is controlled in accordance with the number of colors used in the image to be printed, the size of the transfer material, and the printing direction.

First, the sequence of A4 full-color image recording will be described with reference to FIG. 4 in comparison with the A4 monochrome double-sided image recording.

At the time of full-color image formation, the toner image for four colors is rotated four times on the intermediate transfer member 9 as described above,
The primary transfer of each color toner is performed. And
After all the primary transfer is completed, the secondary transfer is performed on a transfer material (recording paper).

Therefore, the intermediate transfer member 9 rotates at least three times as compared with the monochrome operation. The time required for one rotation of the intermediate transfer member 9 and the time required for the secondary transfer are the same in both monochrome image formation and full color image formation.
This gives time for three rotations. This is utilized in the present embodiment.

That is, a full-color image forming process is performed on the back surface (for example, the second page), and the image is secondarily transferred to a transfer material to perform the reversing process. And the primary transfer process to the intermediate transfer member 9 are sequentially performed. As a result, there is sufficient time until the transfer of the inverted transfer material recorded on the back surface to the registration roller 8 is completed until the primary transfer of the four color toner images is completed.

Therefore, the image recording sequence in this case is as shown in FIG.

That is, first, a yellow (Y) component electrostatic latent image on the second page is formed, a Y component toner image is formed, and primary transfer to the intermediate transfer member 9 is performed. Hereinafter, M, C, and Bk are similarly performed. Then, the full-color toner image formed on the intermediate transfer member 9 is secondarily transferred to a transfer material (recording paper), and is fixed and is sent to a reversing unit. During this time, the primary transfer of the full-color toner image for the first page onto the intermediate transfer member 9 is performed, but before the primary transfer for the last Bk component,
The transfer material recorded on the second page and subjected to the reversal processing is transported in a transferable state.
Next transfer is performed. As a result, the image forming process has been performed on both sides, and thereafter the sheet is discharged to the outside via the fixing device. After this (after page 3), the above processing is repeated.

<Explanation 2 of Full-Color Image Double-sided Recording>
In the above description, the A4 size toner image is generated in the longitudinal direction of the A4 size in the outer color direction of the intermediate transfer body (the direction perpendicular to the rotation axis of the intermediate transfer body) in the A4 full-color image recording sequence, and is recorded on the front and back sides ), But this time, when a toner image in the longitudinal direction of A4 size is generated in the horizontal direction with respect to the rotation axis of the intermediate transfer member, or a toner image such as a letter size smaller than A4 size is generated. The full-color image recording at this time will be described.

As described above, since the diameter of the intermediate transfer member 9 is at least 180 mm, if the short side of the transfer material of A4 or the like is along the outer periphery of the intermediate transfer member 9, Thus, two toner images can be primarily transferred onto the surface of the toner image.

Therefore, the sequence of the recording operation in this case is as shown in FIG.

That is, first, an electrostatic latent image of the Y component on the second and fourth pages is formed, developed with a Y toner image, and primarily transferred to the intermediate transfer member 9. Thereafter, the M, C, and Bk components are also primarily transferred in units of two pages. Thus, when a full-color toner image for two pages is formed,
The secondary transfer to the first transfer material, which has been kept in the registration roller, is started, and the second transfer material is fed. Then, subsequent to the first sheet, the secondary transfer to the second sheet is performed.

The transfer material subjected to the secondary transfer is transported to the reversing unit in a predetermined sequence, and is once transported to a position before the transport roller 7. At the same time, one transfer material is transported from the cassette and transported to the position of the registration roller 8. During this time, the primary transfer of the Y-component toner images on the fourth and first pages to the intermediate transfer member 9 is performed, and the M-component,
This is also performed for the C component and the Bk component. Then, first, the image of the fourth page is transferred to the transfer material conveyed from the cassette.
Next transfer. This transfer material is transported to the reversing unit,
Then, the sheet is conveyed to a position short of the conveying roller 7. The third page is secondarily transferred at the timing shown in FIG. The image of the first page (FIG. 5)
In B), at least the full-color toner image is transferred onto the intermediate transfer member 9 and the first transfer material subjected to the reversal processing is in a standby state at the position of the registration roller 8 by the time of the secondary transfer. And let it do a secondary transfer,
Discharge after fixing.

Thereafter, similarly, pages 6 and 3, 8
An image is generated for each of two pages, that is, a page, a fifth page, and so on. Of the two pages of images, the previously generated image is transferred to the transfer material transported from the cassette, and the transferred transfer material is transported to the reversing unit. Further, an image generated later is secondarily transferred to a transfer material transported from the reversing unit, and the transferred transfer material is carried out of the apparatus. Also, when a table of the last transfer material (for example, the ninth page in the case of recording five sheets and ten pages) is printed, only one image is formed without forming two images, This one
The image on the intermediate transfer body 9 is secondarily transferred to the transfer material and the two images are carried out of the apparatus. According to the above sequence, images are formed in the same order as in the case of monocolor.

In the above example, the printing of ten pages, that is, the printing of even-numbered pages has been described as an example. However, for example, in the case of nine pages, printing corresponding to ten pages is not performed.

Also, under the control of the CPU, the sequence of the image forming apparatus via the I / F unit 5 is described as "single color formation", "full color formation", or "double-sided formation mode". Information (or code intended for it)
Is returned to the host computer 7, and the host computer 7 displays the information.

FIG. 8 shows an example of a display screen during a printing operation in the embodiment. In the drawing, reference numeral 801 denotes a display during single-color printing, 802 denotes a display during full-color printing, and 803 denotes a display during double-side printing. An indicator 804 indicates that a total of six recording media are being printed (prepared). In 804, the difference between the two display modes on the left and the remaining four display modes is the difference between printing on both sides and printing on one side, and C indicates color and M indicates monochrome. I have. By looking at the portion below the indicator 804, the image forming process can be recognized. In the case of the drawing, it is shown that up to the third sheet out of six sheets has been completed.

Information on the color (monochrome or full color) of the image transmitted from the host computer 7, the number of images,
Order and combination of images to be formed (EX.
The information up to the first sheet is a full-color image, and the fifth to tenth sheets is a black monochrome image).
1 indicates what kind of formation sequence is possible from this information (EX. The first to fourth sheets are full-color images, and an image can be formed by a sequence such as "full-color image duplex recording 2"). Since the fifth to tenth images are monochromatic black images, an image forming sequence as shown in FIG. 3 is possible), and it is determined roughly how long image forming is completed. Then, the determination result is returned to the host computer 7. The host computer 7 displays the determination result information on the monitor (806 in FIG. 8), so that the operator can recognize the total required time for image formation and the time until the end of image formation. The inconvenience of the operator going to the image forming apparatus before the image formation is completed and waiting for the image formation to be completed can be eliminated.

When the image forming apparatus is currently in use, the time until completion of the image formation currently being formed (and the time required to form an image to be formed, if any) is taken into consideration. Then, information obtained by adding the determination result determined by the CPU 1 to the already calculated time until the end of the processing is transmitted to the host computer 7. As a result, it is possible to perform notification in consideration of the time required to form the image currently being formed and the image to be formed.

<Explanation of Control Processing Contents> In order to realize the above-described processing, the CPU of FIG. 1 performs the processing. The operation procedure (the program stored in the ROM 2) performed by the CPU 1 will be described. Then, it becomes like the flowchart of FIG. It is assumed that the process of developing the printing bitmap image into the image memory 6 is performed by another task.

First, it is determined in step S1 whether or not double-sided printing is performed. This determination may be made based on a print instruction command from a higher-level device, for example, a host computer, or may be made according to an instruction from the operation panel 4.

If it is determined that the printing is not double-sided printing, that is, it is single-sided printing, the flow advances to step S2 to perform normal single-sided printing.

If it is determined that the printing is double-sided printing, the flow advances to step S3 to determine whether the printing is monochrome (single color) printing.

If it is determined that the printing is monochrome printing, the process proceeds to step S4 to determine whether printing in units of two sheets is possible, that is, two sheets on the intermediate transfer body 9 such as A4 portrait as a printing transfer material. It is determined whether the size and the direction are such that the toner image can be formed.

If printing in units of two sheets is possible, step S
If the printing is performed in units of one sheet, a printing process is performed in step S6 in accordance with each mode.

On the other hand, if it is determined in step S3 that the printing is full-color printing (or printing with the number of colors sufficient for the transport time in the reversing unit), the flow advances to step S7.
Here, too, it is determined whether or not printing in units of two sheets is possible.
8. Branch to any one of step S9.

Here, when the operation proceeds to step S6, the operation is performed in accordance with the sequence shown in FIG. Although the description of step S5 has not been made particularly in the above description, for example, when the secondary transfer time from the intermediate transfer body 9 to the transfer material is compared with the reversing process in the reversing unit, when the latter is short, the single color , And the primary transfer is substantially possible in the sequence of FIG. In other words, when transferring two sheets simultaneously,
Since the second transfer to the second transfer material is performed while the reversing process of the first transfer material is performed, the first transfer material is transported to the position of the registration roller 8 by the time of completion. It is.

When the process proceeds to step S8, the sequence of FIG. 5 may be followed, and when the process proceeds to step S9, the sequence of FIG. 4 may be followed.

Here, the specific processing content of step S9 (full-color one-sided double-sided recording processing) will be described with reference to the flowchart of FIG.

First, in step S11, "2" is given as an initial value to a variable i, and it is determined in step S12 whether double-sided printing has been completed. When it is determined that the process has been completed, the present process is terminated, and the process returns to the process of FIG.

If it is determined that the process has not been completed, the flow advances to step S13 to determine whether the content of the variable i is even or odd. Since i = 2 in the initial state, the process proceeds to step S14, where the formation of the electrostatic latent image of the Y component and the primary transfer to the intermediate transfer body 9 for the i-th page full-color image are started. Thereafter, the same process is performed for the other M, C, and Bk components.

When the process proceeds to step S15, the corresponding transfer material is fed from the paper feed cassette.

When the process proceeds to step S16, the last B
When the primary transfer to the k component is performed and the standby of the transfer material is determined by the sensor provided near the registration roller 8, the secondary transfer is started in step S17. Then, in step S18, it is set so that the transfer to the reversing unit is performed, and in step S19, the variable i is decremented by "1", and the process returns to step S13.

Returning to step S13, since the variable i becomes an odd number, the flow advances to step S20 to start primary transfer of the page indicated by the variable i. This is the same as step S14 described above. During the primary transfer, the transfer material subjected to the secondary transfer in step S17 is reversed by the reversing unit, and is conveyed toward the registration roller 8.

In step S21, it is determined whether or not the primary transfer of the last Bk component has been performed, and a reversal transfer material has been conveyed to the registration roller 8. Then, in step S22, the secondary transfer is started. In step S23, the output destination is set to the discharge tray. In step S24, "3" is added to the variable i.

Thereafter, by repeating the processing of step 12 and subsequent steps, a full-color image is printed on both sides in a sequence as shown in FIG.

According to the present embodiment as described above,
By appropriately switching the image forming sequence in accordance with the number of recording colors, the size of the transfer material, and the direction thereof, the image memory can be effectively used, and the printing process can be performed at high speed.

In the above description, the printer device has been described. However, the present invention may be applied to, for example, a copying machine.

In the above description, the A4 size is used as an example. However, the LETTER size can be realized with the same concept, and the present invention is not limited by the size.

Further, in the embodiment, the example in which the last fixed surface is discharged as the lower surface has been described. However, the present invention is not limited to this, and the present invention may be applied to an apparatus having a mechanism for discharging the last fixed surface as the upper surface. . In this case, for example, in the sequence of FIG. 4, image formation is performed in the order of 2, 1, 4, 3,... Pages, but is performed in the sequence of 1, 2, 3, 4,. As a result, is the capacity of the image memory the same,
Alternatively, it can be slightly reduced.

Further, in the embodiment, whether or not monochrome is set,
Although it was determined whether or not simultaneous image formation is possible, for example, by referring to an image forming sequence table separately prepared based on information serving as these criteria,
An image forming sequence may be determined.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copier, a facsimile). Device).

Further, an object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and a computer (or CPU) of the system or the apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

Examples of the storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and CD.
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0093]

As described above, according to the present invention, it is possible to perform optimal double-sided printing in accordance with the number of recording colors or the size and direction of the recording medium.

[0094]

[Brief description of the drawings]

FIG. 1 is a block diagram of a control system of an image forming apparatus according to an embodiment.

FIG. 2 is a sectional structural view of the image forming apparatus according to the embodiment.

FIG. 3 is a diagram illustrating an image forming sequence for each monochrome sheet.

FIG. 4 is a diagram illustrating an image forming sequence in units of one full color sheet.

FIG. 5 is a diagram illustrating an image forming sequence in units of two full-color images.

FIG. 6 is a flowchart illustrating an image processing procedure according to the embodiment.

FIG. 7 is a flowchart showing a procedure of image processing for one full color sheet in step 9 in FIG. 6;

FIG. 8 is a diagram showing a display example of a display screen in the embodiment.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03G 21/00 370 B41J 3/00 SH04N 1/00 108 B 1/60 H04N 1/40 D 1 / 46 1/46 Z

Claims (27)

[Claims] 1. An image forming apparatus for sequentially forming a plurality of images on a recording medium, comprising: an intermediate transfer unit capable of holding an image corresponding to the image; Transfer means for transferring; reversing means for reversing the recording medium to form an image on the back surface of the recording medium on which the image has been formed; and sequentially forming the plurality of images on both surfaces of the recording medium using the reversing means. An image forming apparatus for controlling the image forming sequence of the plurality of images in accordance with image forming conditions. 2. The image forming apparatus according to claim 1, wherein the image forming condition is a forming color condition indicating whether a single color is formed or a full color is formed. 3. The image forming condition according to claim 1, wherein the image forming condition is a condition for forming a plurality of images on the intermediate transfer unit at the same time or not forming a plurality of images at the same time. The image forming apparatus as described in the above. 4. The image forming apparatus according to claim 1, wherein the image forming condition is a recording medium direction condition indicating a conveying direction of the recording medium to the image forming apparatus. 5. An image forming apparatus according to claim 1, wherein an image to be transferred next is formed in said intermediate transfer means at the time of reversal processing by said reversal means. 6. An image forming apparatus according to claim 1, wherein an image forming condition for simultaneously forming a plurality of images on said intermediate transfer unit is one.
In a condition where two images are formed on the recording medium in a single sequence and a plurality of images are not simultaneously formed on the intermediate transfer unit, one image is formed on the recording medium in one rotation sequence of the intermediate transfer unit. The image forming apparatus according to claim 3, wherein the image forming apparatus is formed on the image forming apparatus. 7. A determination unit for determining a time required for image formation as a result of the image formation control by the control unit, and a determination result of the determination unit, and an external device that transmits information indicating the plurality of images. The image forming apparatus according to claim 1, further comprising a first notifying unit that notifies the apparatus. 8. The image processing apparatus according to claim 1, further comprising a second notifying unit that notifies an external storage device that has transmitted the information indicating the plurality of images of an image forming sequence used in the image forming control by the control unit. The image forming apparatus according to claim 1, wherein: 9. The image forming apparatus according to claim 7, wherein the first notifying unit notifies the determination result by adding a time considering the occupation state of the image forming apparatus. 10. An intermediate transfer unit capable of holding an image corresponding to an image, a transfer unit for transferring an image on the intermediate transfer unit to a recording medium, and forming an image on a back surface of the recording medium on which the image has been formed. Reversing means for reversing the recording medium in order to
A method for controlling an image forming apparatus for sequentially forming a plurality of images on a recording medium, the method comprising: forming the plurality of images sequentially on both sides of the recording medium using the reversing means A control step of controlling image formation according to image formation conditions in a sequence. 11. The method according to claim 10, wherein the image forming condition is a forming color condition indicating whether a single color is formed or a full color is formed. 12. The image forming condition according to claim 10, wherein the image forming condition is a formed image number condition indicating whether to form a plurality of images on the intermediate transfer unit at the same time or not to form a plurality of images at the same time. The control method of the image forming apparatus described in the above. 13. The method according to claim 10, wherein the image forming condition is a recording medium direction condition indicating a conveying direction of the recording medium to the image forming apparatus. 14. The control method for an image forming apparatus according to claim 10, wherein an image to be transferred next is formed in said intermediate transfer means at the time of reversal processing by said reversal means. 15. An image forming condition in which a plurality of images are simultaneously formed on the intermediate transfer unit, two images are formed on the recording medium in one sequence of the intermediate transfer unit, and 13. The method according to claim 12, wherein one image is formed on the recording medium by one rotation sequence of the intermediate transfer unit in a condition that a plurality of images are not formed at the same time. 16. A determination step of determining a time required for image formation as a result of the image formation control by the control step, and determining the determination result of the determination step by using an external device that transmits information indicating the plurality of images. The method according to claim 10, further comprising a first notification step of notifying the apparatus. 17. The image processing apparatus according to claim 17, further comprising a second notification step of notifying an image forming sequence used in the image forming control by the control step to an external storage device that has transmitted information indicating the plurality of images. The method for controlling an image forming apparatus according to claim 10, wherein: 18. The control method for an image forming apparatus according to claim 16, wherein in the first notifying step, the determination result is notified by adding a time in consideration of an occupation state of the image forming apparatus. . 19. An intermediate transfer unit capable of holding an image corresponding to an image, a transfer unit for transferring an image on the intermediate transfer unit to a recording medium, and forming an image on a back surface of the image-formed recording medium. An inverting means for inverting the recording medium, wherein the storage medium stores a control program for sequentially forming a plurality of images on the recording medium. A storage medium storing a program code of a control step of controlling image formation in accordance with image formation conditions in a sequence of forming the plurality of images when sequentially forming the plurality of images on both sides. 20. The storage medium according to claim 19, wherein the image forming condition is a forming color condition indicating whether a single color is formed or a full color is formed. 21. The image forming condition according to claim 19, wherein the image forming condition is a formed image number condition indicating whether a plurality of images are formed on the intermediate transfer unit at the same time or not. The storage medium according to the above. 22. The storage medium according to claim 19, wherein said image forming condition is a recording medium direction condition indicating a conveying direction of said recording medium to said image forming apparatus. 23. The storage medium according to claim 19, wherein an image to be transferred next is formed in said intermediate transfer means at the time of reversal processing by said reversal means. 24. An image forming condition in which a plurality of images are simultaneously formed on the intermediate transfer means, two images are formed on the recording medium by one sequence of the intermediate transfer means, and 22. The storage medium according to claim 21, wherein one image is formed on said recording medium by one rotation sequence of said intermediate transfer means in a condition in which a plurality of images are not formed at the same time. 25. A program code of a determining step of determining a time required for image formation as a result of the image forming control by the control step, and information indicating the plurality of images, the determination result of the determining step being transferred. 20. The apparatus according to claim 19, further comprising a program code of a first notification step of notifying an external device that has made the notification.
The storage medium according to the above. 26. A program code for a second notification step of notifying an external storage device that has transmitted information indicating the plurality of images, of an image formation sequence used in image formation control by the control step. 20. The storage medium according to claim 19, comprising: 27. The storage medium according to claim 25, wherein in the first notification step, the determination result is notified by adding a time considering a state of occupation of the image forming apparatus.