JP2000108320A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an imaging apparatus in which imaging time can be shortened without varying the circumferential speed of an intermediate transfer belt. SOLUTION: An intermediate transfer belt 25 has imaging areas A, B corresponding to sheets A, B and an imaging head 15 and a transfer roller 22 are disposed oppositely on the opposite sides of the intermediate transfer belt 25. After images are formed continuously in the areas A, B, the image in the area B is transferred to the sheet B and the image in the area A is transferred to the sheet A. According to the arrangement, imaging time for two sheets can be shortened to 2/3 as compared with a conventional system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming an image on an image forming medium by forming an image on a peripheral surface of a rotating body with an image forming material and transferring the image to the image forming medium. The forming apparatus is suitable as an image forming apparatus capable of reducing an image forming time.

[0002]

2. Description of the Related Art Conventionally, as the image forming apparatus, for example, the one shown in FIG. 9 is known. FIGS. 9A to 9D are explanatory diagrams showing the operation of the image forming apparatus from the start of image formation to the end of image transfer. The image forming apparatus includes a driving roller 18. The driven roller 2 is opposed to the driving roller 18 at a predetermined interval.
6 are provided. An intermediate transfer belt 30 is wound around the peripheral surfaces of the driving roller 18 and the driven roller 26. The image forming head 15 is provided at a position facing the upper surface of the intermediate transfer belt 30, and the image forming head 1
5, a transfer roller 22 is provided at a position facing the lower surface of the intermediate transfer belt 30. A transfer driven roller 32 is provided inside the intermediate transfer belt 30 at a position facing the transfer roller 22, and a peeling claw 24 is provided on the left side of the transfer roller 22. A pair of paper feed rollers 20 is provided diagonally below the transfer roller 22 on the right side.

Next, a series of operations of the image forming apparatus having the above configuration will be described. Note that the length of the image forming area is Lp
, The length of the non-image forming area is Ls, and (Lp + L
Let s) be the total length L of the intermediate transfer belt. First, when image data is input from a computer or the like connected to the image forming apparatus, the drive roller 18 rotates in a direction indicated by an arrow F1, and the intermediate transfer belt 30 rotates in a direction indicated by an arrow F2. Subsequently, the intermediate transfer belt 30 is moved to the image formation start point P.
Is reached, the image forming head 15 is driven based on the image data, and the image forming head 15
The ink is ejected to the image forming area on 0, and image formation is started (FIG. 9A). When the image formation is completed (FIG. 9B), the feeding of the sheet 31 by the sheet feeding roller 20 is started, and the transfer roller 22 is moved to the intermediate transfer belt 30.
Move towards. Subsequently, the image forming start point P of the intermediate transfer belt 30 is set to the transfer roller 22 and the transfer driven roller 3.
In synchronization with the timing of reaching the transfer point between
1 reaches the transfer point, and the intermediate transfer belt 3
9 is transferred onto the paper 31 (FIG. 9).
(C)). Then, the transferred paper 31 is placed on the peeling claw 24.
As a result, the toner is peeled off from the peripheral surface of the intermediate transfer belt 30 and discharged onto a tray or the like (not shown) (FIG. 9D). Thereafter, the intermediate transfer belt 30 returns to the image forming start position shown in FIG.

[0004]

By the way, in the above-mentioned image forming apparatus, in order to reduce scattering of ink droplets ejected from the image forming head 15, the direction of ink droplet ejection and the direction of gravity are the same. The image forming head 15 is disposed above the intermediate transfer belt 30 and downward. On the other hand, the transfer roller 22 and the transfer driven roller 32
The reason is that it is necessary to dispose the paper feed roller 20, the peeling claw 24, and the like, and to simplify the paper transport mechanism by performing the supply and discharge of the paper almost linearly. It is arranged below the intermediate transfer belt 30. That is, the image forming head 15 and the transfer roller 22 and the transfer driven roller 32 are installed separately. However, when the transfer operation is being performed, the transfer 22
And the intermediate transfer belt 30 by the transfer driven roller 32.
Is pressed, the peripheral speed of the intermediate transfer belt 30 is changed, and vibration due to the pressure is transmitted to the intermediate transfer belt 30, so that image formation cannot be performed. for that reason,
As described above, transfer is performed after image formation is completed.

Here, the above-described image forming apparatus performs one cycle operation from the start of image formation to the end of transfer and back to the original image formation start point.
Is calculated. First, the moving distance d of the intermediate transfer belt 30 at the end of the image formation shown in FIG.
Since 1 is equal to the length Lp of the image forming area, d1 = L
p. Then, as shown in FIG. 9C, the moving distance d2 required until the image formation start point P reaches the transfer point.
Is the idling distance until the image formation start point P reaches the transfer point, and therefore d2 = (L / 2 + Ls). Then, as shown in FIG. 9D, the distance d3 to be moved from the start of the transfer to the end of the transfer is the length of the image forming area itself, so that d3 = Lp. The transfer distance d4 required for the image formation start point P to return to the original image formation start point P shown in FIG. 9A after the end of the transfer is d4 = (L
s + L / 2). This moving distance d4 is also the idling distance. Therefore, the total moving distance d = d1 + d2 + d3
+ D4 = Lp + (L / 2 + Ls) + Lp + (Ls + L /
2) = 2Lp + L + 2Ls = 2 (Lp + Ls) + L = 2
L + L = 3L.

That is, in the conventional image forming apparatus, it is necessary to rotate the intermediate transfer belt 30 three times in order to form an image on one sheet, of which (d2 + d4) = (L
/ 2 + Ls) + (Ls + L / 2) = L + 2Ls is the idle running distance. That is, a distance obtained by adding twice the non-image forming area to one rotation of the intermediate transfer belt 30 is a useless distance in which neither image formation nor transfer is performed. Here, if the image forming speed of the image forming head 15 and the peripheral speed of the intermediate transfer belt 30 are increased, the image forming time can be reduced, but the image quality degree is not preferable. Therefore, the conventional image forming apparatus has a problem that the image forming time cannot be reduced without changing the peripheral speed of the intermediate transfer belt 30.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of reducing an image forming time without changing a peripheral speed of a rotating body having a peripheral surface on which an image is formed.

[0008]

According to the present invention, in order to achieve the above object, an image forming means for forming an image and a peripheral surface on which an image is formed by the image forming means are provided. And a transfer means for transferring an image formed on the peripheral surface to the paper by bringing the paper into contact with the peripheral surface of the rotary body. The surface is divided into first and second peripheral surfaces along a circumferential direction with a recording start position by the image forming unit and a transfer position by the transfer unit as boundaries, and the first and second peripheral surfaces are divided. A technical means is adopted in which each surface has a recording area along the circumferential direction at least an integral multiple of the length of the sheet.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a plurality of sheets of paper are formed by using a recording area of at least one of the first and second peripheral surfaces. Control means for controlling the image forming means and the transfer means so that after the image formation for a plurality of sheets is completed and the image formation for the plurality of sheets is completed, the plurality of images are transferred to the sheet. The technical means of having

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image forming operation by the image forming unit and the transfer by the transfer unit are overlapped. A technical means is adopted which has a second control means for controlling the image forming means and the transfer means so as not to alternately and repeatedly perform the operation.

According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, wherein the rotator is formed as an endless belt. adopt.

[0012]

According to the first to fourth aspects of the present invention, the circumferential surface of the rotating body on which an image is formed is formed along the first and second circumferential directions along the circumferential direction with the recording start position and the transfer position as boundaries. Since the first and second peripheral surfaces each have a recording area along the circumferential direction that is at least an integral multiple of the length of the sheet, the first and second peripheral surfaces are separated during one rotation of the rotating body. And an image of at least an integral multiple of the sheet can be formed on the second peripheral surface. Therefore, as before,
Useless rotation of the rotator can be reduced as compared with the case where a rotator having only a recording area for one sheet is used, so that the image forming time can be reduced without changing the peripheral speed of the rotator. .

[0013] In particular, according to the second aspect of the present invention, the first control means uses the recording area of at least one of the first and second peripheral surfaces to form an image for a plurality of sheets. Is performed, and after the image formation for the plurality of sheets is completed,
The image forming unit and the transfer unit are controlled so that the plurality of images are transferred onto a sheet. In other words, by continuously performing image formation for a plurality of sheets and then transferring the images for a plurality of sheets to a sheet, the rotation and rotation of the image are performed more than in the conventional case where image formation and transfer are performed one by one. Since unnecessary rotation of the body can be reduced, the image forming time can be reduced. For example, in the above-described conventional image forming apparatus, 1
Since the moving distance of the intermediate transfer belt (rotary body) required from the start of image formation to the end of transfer of two sheets is 3L when the total length of the intermediate transfer belt is L, 2
× 3L = 6L, for example, the present invention
In the case where the image forming apparatus according to the embodiment includes a rotator capable of forming an image for two sheets, an image for two sheets is continuously formed on the rotator, and then the image is formed. In a configuration in which transfer is continuously performed on a sheet of paper, the moving distance of the intermediate transfer belt is 4L, and the conventional 4L / 6L = 2/3.
Becomes Therefore, according to the image forming apparatus of the second aspect, the image forming time can be reduced to 2/3 of the conventional time.

According to the third aspect of the invention, the second control means alternately repeats the image formation by the image forming means and the transfer by the transfer means so that the image forming operation and the transfer operation do not overlap. The image forming unit and the transfer unit are controlled as described above. That is, in the above-described conventional image forming apparatus, the moving distance of the intermediate transfer belt (rotary body) required from the start of image formation on one sheet to the end of transfer is 3 L when the total length of the intermediate transfer belt is L. Therefore, for three sheets, 3 × 3L = 9 L. For example, in an image forming apparatus according to a second embodiment of the present invention described later, in a configuration in which image formation and transfer are alternately repeated, an intermediate transfer belt is used. Is 8L, which is 8L / 9
L = 8/9. Therefore, according to the image forming apparatus of the third aspect, the image forming time can be reduced to 8/9 of the conventional one.

[0015] In particular, the technical means of claims 1 to 3 are suitably adopted in a case where the rotating body is formed in an endless belt shape as in the invention of claim 4.
That is, if the rotating body is formed in the shape of an endless belt, it is possible to easily cope with the above-described control contents by changing the entire length of the belt.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an image forming apparatus according to the present invention will be described below with reference to the drawings. In the following embodiments, as an image forming apparatus of the present invention, an image forming apparatus that forms an image with ink on an intermediate transfer belt and transfers the image to a sheet will be described as a representative. FIG.
FIGS. 1A to 1C are explanatory diagrams showing an operation from the start of image formation in the area A to the end of image formation in the area B by the image forming apparatus of the first embodiment. 2
(D) to FIG. 2 (F) are explanatory diagrams showing the operation from the start of the transfer of the B area to the end of the transfer of the A area. FIG. 3 is an explanatory diagram showing a block diagram of an electrical configuration of the image forming apparatus shown in FIGS. Note that the same components as those of the conventional image forming apparatus shown in FIG. Also,
It is assumed that the same sheet as that used in the conventional image forming apparatus shown in FIG. 9 is used, and the total length of the intermediate transfer belt of the conventional image forming apparatus is L. The length of the image forming area for one sheet is Lp, and the length of the non-image forming area is Ls. Further, two sheets of paper A and paper B are used, and the image forming areas of each paper are assumed to be an A area and a B area, respectively. Further, the image formation starting points of the area A and the area B on the intermediate transfer belt are respectively P
A and PB.

As shown in FIGS. 1 and 2, the intermediate transfer belt 25 provided in the image forming apparatus
The belt is formed at the belt length of the region and the two non-image forming regions Ls. A belt marker sensor 23 that detects that the image forming start point has reached the image forming point of the image forming head 15 is located at a position facing the upper surface of the intermediate transfer belt 25 and to the left of the image forming head 15. Is provided.

Next, the electrical configuration of the image forming apparatus 10 will be described with reference to FIG. In the image forming apparatus 10,
A CPU 11 that controls the image forming head 15, controls the intermediate transfer belt 25, controls the transfer roller 22, controls the sheet feed roller 20, and the like is provided. Also, CPU
The ROM 12 stores a computer program for executing the various controls described above,
, A driver IC 14 for driving the image forming head 15, a belt marker sensor 23, and a buffer 27 for temporarily storing image data output from the external computer 28. And are connected. Further, the image forming apparatus 10 includes a driving motor 17 for driving a driving roller 18 and a driving motor 19 for driving a paper feeding roller 20.
And a drive motor 21 for driving the transfer roller 22. These drive motors are controlled by a control circuit 16, and the control circuit 16 is connected to the CPU 11.

Next, the operation of the image forming apparatus 10 from the start of image formation to the end of transfer will be described with reference to FIG. FIG. 4 is a flowchart illustrating control executed by the CPU 11 in order for the image forming apparatus 10 to perform an operation from the start of image formation to the end of transfer. 1 and 2, the broken line on the intermediate transfer belt 25 is
1A and 1B show an image non-formed area, and FIGS. 2E and 2F show a transferred area. The solid line indicates an image-formed area. Further, a point at which an image is formed by the image forming head 15 is referred to as an image forming point, and a point at which transfer is performed by the transfer roller 22 and the transfer driven roller 32 is referred to as a transfer point.

When the CPU 11 receives an image forming command from the external computer 28 and inputs image data (step (hereinafter abbreviated as S) 10: Yes), the CPU 11 sends a drive signal for driving the drive motor 17 to the control circuit 16 Output and drive the intermediate transfer belt 25 (S12). Then, CP
When U11 detects that the belt marker sensor 23 is ON, that is, when the image formation start point PA of the area A reaches the image formation point (S14: Yes), U11 outputs the image data stored in the buffer 27 to the driver IC 14. To drive the image forming head 15 to form an image in the area A (S1).
6, FIG. 1 (A)). Subsequently, when completing the image formation in the area A (S18: Yes), the CPU 11 starts the image formation in the area B (S20, FIG. 1B). Here, the distance d1 that the intermediate transfer belt 25 has moved until the image formation start point PB of the B area reaches the image formation point is obtained by adding the length Ls of the non-image formation area to the length Lp of the A area ( Lp +
Ls).

Subsequently, when the CPU 11 completes the image formation in the area B (S22: Yes, FIG. 1C), the CPU 11 outputs a drive signal for driving the drive motor 19 to the control circuit 16 to supply the paper feed roller. 20 is driven to transfer the paper B to the transfer roller 2
2 (S24, FIG. 2D). here,
Since the distance d2 that the intermediate transfer belt 25 has moved from the start of image formation to the end of image formation in the B area is equal to the length of the B area, it becomes Lp. Subsequently, the CPU 11 outputs a drive signal for driving the drive motor 21 to the control circuit 16 to drive the transfer roller 22. The transfer roller 22 moves toward the transfer driven roller 32 while rotating, and the image formation start point of the sheet B reaches the transfer point in synchronization with the timing at which the image formation start point PB of the B area reaches the transfer point. , B
The image of the area is transferred to paper B (S26). Where B
The distance d3 traveled by the intermediate transfer belt 25 from the end of the image formation in the area to the point at which the image formation start point PB in the area B reaches the transfer point is equal to the length of the non-image formation area, and is Ls. .

Subsequently, when the transfer of the area B is completed (S28: Yes), the CPU 11 supplies the sheet A (S3).
0), area A is transferred to sheet A (S32, FIG. 2)
(E)). Here, the distance d4 that the intermediate transfer belt 25 has moved from the start of the transfer of the B area to the start of the transfer of the A area after the transfer of the B area is completed is equal to the length Lp of the B area.
Is added to the length Ls of the non-image forming area (Lp + Ls)
Becomes Subsequently, the CPU 11 ends the transfer of the area A (S34: Yes, FIG. 2 (F)), and detects the ON of the belt marker sensor 23, that is, when the image formation start point PA reaches the image formation point (S36). : Yes), the rotation of the intermediate transfer belt 25 is stopped (S38). Here, the image formation start point P of the area A after the image formation of the area A is completed.
The distance d5 that the intermediate transfer belt 25 has moved until B reaches the image forming point is (Lp + Ls) obtained by adding the length Ls of the non-image forming area to the length Lp of the A area.

As described above, the image forming apparatus 10 operates in S1
0 to S38 as one cycle, and
An image is formed on a sheet of paper. Here, when the total moving distance d of the intermediate transfer belt 25 in the case of executing the above one cycle is obtained, d = (Lp + Ls) + Lp + Ls + (Lp + L
s) + Lp + Ls = 4Lp + 4Ls = 4 (Lp + Ls)
= 4L. That is, the image forming apparatus 10 moves the intermediate transfer belt 25 by a distance corresponding to four revolutions of the entire length of the conventional intermediate transfer belt 30 in order to form an image on two sheets. Here, in the conventional image forming apparatus, the moving distance per sheet is 3 L, and 3 L × 2 =
Since it is 6 L, the image forming apparatus 10 of the present embodiment has the moving distance of the intermediate transfer belt 25 shorter by 4 L / 6 L = ２ than the conventional image forming apparatus. Therefore, if the image forming apparatus 10 of the first embodiment is used, the image forming time for two sheets can be reduced to 2/3 of the conventional one without changing the peripheral speed of the intermediate transfer belt 25.

Next, an image forming apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG.
5A to 5C are explanatory diagrams showing the operation from the start of image formation of the area A to the end of transfer of the area A by the image forming apparatus of the second embodiment, and FIG. (D) to FIG. 6 (F) show the state after starting the image formation of the area C.
It is an explanatory view showing the operation until the transfer of the area is completed,
7 (G) to 7 (I) are explanatory diagrams showing the operation from the start of the image formation of the B area to the end of the transfer of the B area. FIG. 8 is a diagram showing a state in which the image forming apparatus according to the second embodiment performs an operation from the start of image formation to the end of transfer.
6 is a flowchart illustrating control executed by U. The image forming apparatus according to the second embodiment is characterized in that the image forming time can be reduced as compared with the related art by alternately repeating image formation and transfer of three sheets. The description of the same parts as in the first embodiment will be omitted. In the following, it is assumed that images are formed on paper A, paper B, and paper C.

As shown in FIGS. 5 to 7, an image forming apparatus 40 according to the second embodiment includes an area A corresponding to sheet A, an area B corresponding to sheet B, and a section C corresponding to sheet C.
An intermediate transfer belt 33 having three areas and three non-image forming areas is provided. The distance between the image forming point and the transfer point is a length obtained by adding the length Ls of the non-image forming area to the length Lp of one image forming area, that is, the distance between the image forming point and the transfer point in the conventional image forming apparatus shown in FIG. The total length L of the provided intermediate transfer belt 30 is set.

Next, the operation of the image forming apparatus 40 from the start of image formation to the end of transfer will be described with reference to FIG. The CPU 11 receives the image forming command (S5).
0: Yes), and drives the intermediate transfer belt 33 (S5).
2) When ON of the belt marker sensor 23 is detected (S
54: Yes), the image formation of the area A is performed (S56, FIG. 5A). Subsequently, when the image formation in the area A is completed (S58: Yes), the CPU 11 supplies the sheet A (S58).
60), the image in the area A is transferred to the sheet A (S62, FIG. 5B). Here, the distance d1 that the intermediate transfer belt 25 has moved until the image formation start point PA of the area A reaches the transfer point is equal to the length Lp of the area A and the length L of the non-image formation area.
(Lp + Ls) obtained by adding s.

Subsequently, when the transfer of the area A is completed (S64: Yes, FIG. 5C), the CPU 11 forms an image of the area C (S66, FIG. 6D). Here, the distance d2 that the intermediate transfer belt 25 has moved from the start of the transfer to the end of the transfer in the area A is equal to the length of the area A, and thus becomes Lp. Further, the distance d3 that the intermediate transfer belt 33 has moved from the end of the transfer of the area A to the point at which the image forming start point PC of the area C reaches the image forming point is equal to the length of the non-image forming area. Ls. Subsequently, the CPU 11
When the image formation in the area C is completed (S68: Yes), the sheet C is supplied (S70), and the area C is transferred to the sheet C (S72, FIG. 6E). Here, the distance d4 that the intermediate transfer belt 33 has moved from the start of the image formation in the area C to the end of the image formation to the start of the transfer in the area C is C
This is (Lp + Ls) obtained by adding the length Ls of the non-image forming area to the length Lp of the area.

Subsequently, when the transfer of the area C is completed (S74: Yes, FIG. 6 (F)), the CPU 11 forms an image of the area B (S76, FIG. 7 (G)). Here, the distance d5 traveled by the intermediate transfer belt 33 from the end of the transfer of the area C to the point at which the image formation start point PB of the area B reaches the image formation point is the distance d5 corresponding to two image formation areas and non-image formation. Since it passes through three regions, it is (2Lp + 3Ls).
Subsequently, when completing the image formation of the B area (S78: Yes), the CPU 11 transfers the B area (S80, FIG. 7H), and ends the transfer of the B area (S82: Yes,
7 (I), when it is detected that the image formation start point PC has reached the image formation point (S84: Yes), the rotation of the intermediate transfer belt 33 is stopped (S86). Here, the distance d6 that the intermediate transfer belt 33 has moved from the start of the transfer to the end of the transfer of the B area is the distance obtained by adding the length Ls of the non-image forming area to the length Lp of the B area, and thus (Lp + Ls)
Becomes The distance d7 that the intermediate transfer belt 33 has moved from the end of the transfer in the area B to the point at which the image formation start point PC in the area C reaches the image formation point is (Lp + Ls).
Becomes

As described above, the image forming apparatus 40 operates in S5
0 to S86 as one cycle, 3 for paper A to paper C
An image is formed on a sheet of paper. For the next new sheet, the image forming start point PC in the C area shown in FIG.
To form an image. Here, when the total movement distance d of the intermediate transfer belt 25 in the case where the above one cycle is executed is obtained, d = (Lp + Ls) + Lp + Ls + (Lp + Ls)
+ Lp + (2Lp + 3Ls) + (Lp + Ls) + Lp +
Ls = 8Lp + 8Ls = 8 (Lp + Ls) = 8L. That is, the image forming apparatus 40 moves the intermediate transfer belt 33 by a distance corresponding to eight turns of the conventional intermediate transfer belt 30 in order to form an image on three sheets. Here, in the conventional image forming apparatus, the moving distance per sheet is 3 L, and 3 L × 3 = 9 L for three sheets. Therefore, the image forming apparatus 40 according to the second embodiment uses the intermediate transfer. The moving distance of the belt 33 is 8 L longer than that of the conventional image forming apparatus.
/ 9L = 8/9 short. Therefore, if the image forming apparatus 40 according to the second embodiment is used, the image forming time of three sheets can be reduced without changing the peripheral speed of the intermediate transfer belt 33 by 8/9.
Can be shortened to

In the above-described embodiment, the case where the image is formed on two sheets and three sheets is described. However, the present invention can be applied to the case where the image is formed on four or more sheets. Further, in each of the embodiments described above, the image forming apparatus of the present invention that transfers an image using an intermediate transfer belt has been described as a representative, but the image forming apparatus that transfers an image using an intermediate transfer drum is also described. The invention can be applied. Incidentally, the image forming head 15 corresponds to the image forming unit of the present invention, the intermediate transfer belt 25 corresponds to a rotating body, and the transfer roller 22 and the transfer driven roller 32 correspond to a transfer unit. Two peripheral surfaces in the case where the peripheral surface of the intermediate transfer belt 25 is divided by the boundary between the image forming point and the transfer point correspond to the first and second peripheral surfaces of the present invention.
Further, S10 to S38 in FIG.
Function as the first control means according to the second aspect, and S50 to S86 in FIG. 8 function as the second control means according to the third aspect.

[0031]

As described above, claims 1 to 4 are as described above.
According to the invention described in (1), the peripheral surface of the rotating body on which the image is formed is divided into the first and second peripheral surfaces along the circumferential direction with the recording start position and the transfer position as boundaries, and Since the first and second peripheral surfaces each have a recording area along the circumferential direction that is at least an integral multiple of the length of the sheet, the first and second peripheral surfaces respectively correspond to the first and second peripheral surfaces during one rotation of the rotating body. An image at least an integral multiple of the sheet can be formed.
Therefore, useless rotation of the rotating body can be reduced as compared with a conventional rotating body having only a recording area for one sheet, so that the peripheral speed of the rotating body is not changed. Can shorten the image forming time.

In particular, according to the second aspect of the present invention, image formation for a plurality of sheets is performed using a recording area of at least one of the first and second peripheral surfaces. After the image formation for a plurality of sheets is completed, the image forming apparatus includes a first control unit that controls the image forming unit and the transfer unit so that the plurality of images are transferred to a sheet. It is possible to reduce unnecessary rotation of the rotating body and shorten the image forming time as compared with the case where transfer is performed one sheet at a time. For example, in the case where the rotating body has a configuration capable of forming an image for two sheets of paper, and after forming an image for two sheets of paper on the rotating body, the image is transferred to the sheet.
The image forming time for two sheets can be reduced to 2/3 of the conventional one.

According to the third aspect of the present invention, the image forming means so that the image formation by the image forming means and the transfer by the transfer means are alternately repeated so that the image forming operation and the transfer operation do not overlap. In addition, since the image forming apparatus includes the second control means for controlling the transfer means, it is possible to reduce unnecessary rotation of the rotating body and shorten the image forming time as compared with the conventional one. For example, in the case where the rotating body is capable of forming an image for three sheets, a cycle of forming an image for one sheet on the rotating body and then transferring the image to the sheet is repeated, The image forming time for three sheets can be reduced to 8/9 of the conventional one.

In particular, the invention of claims 1 to 3 is
According to a fourth aspect of the present invention, the rotating body is suitably employed in an endless belt. That is, if the rotating body is formed in the shape of an endless belt, it is possible to easily cope with the above-described control contents by changing the entire length of the belt.

[Brief description of the drawings]

FIGS. 1A to 1C show an operation from the start of image formation of an area A to the end of image formation of an area B by the image forming apparatus according to the first embodiment of the present invention; FIG.

FIGS. 2D to 2F are views illustrating a state after the image forming apparatus according to the first embodiment of the present invention starts transfer of an area B;
FIG. 9 is an explanatory diagram illustrating an operation until transfer of an area is completed.

FIG. 3 is an explanatory diagram showing a block diagram of an electrical configuration of the image forming apparatus shown in FIGS. 1 and 2;

FIG. 4 is a flowchart illustrating control executed by a CPU 11 in order for the image forming apparatus 10 to perform operations from the start of image formation to the end of transfer.

FIGS. 5A to 5C show an operation from the start of image formation of an area A by the image forming apparatus according to the second embodiment of the present invention to the end of transfer of the area A; FIG.

FIGS. 6 (D) to 6 (F) show an operation from the start of image formation of the area C by the image forming apparatus according to the second embodiment of the present invention to the end of transfer of the C area. FIG.

FIGS. 7G to 7I show an operation from the start of image formation of the B area to the end of transfer of the B area by the image forming apparatus according to the second embodiment of the present invention; FIG.

FIG. 8 is a flowchart illustrating control executed by a CPU 11 in order for the image forming apparatus 40 to perform operations from the start of image formation to the end of transfer.

FIGS. 9A to 9D are explanatory views showing the operation of the conventional image forming apparatus from the start of image formation to the end of transfer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 image forming apparatus 11 CPU (first control means, second control means) 15 image forming head (image forming means) 18 drive roller 20 paper feed roller 22 transfer roller (transfer means) 23 belt marker sensor 24 paper separating claw 25 Intermediate transfer belt (rotating body) 33 Transfer driven roller (transfer unit) A paper B paper A area Paper A image formation area B area Paper B image formation area PA Image formation start point in A area PB Image formation in B area Starting point

Claims (4)

[Claims] An image forming means for forming an image, a rotating body having a peripheral surface on which an image is formed by the image forming means, and a sheet formed on the peripheral surface by contacting a sheet with the peripheral surface of the rotating body. And a transfer unit for transferring the transferred image to the sheet, wherein the circumferential surface of the rotating body has a circumferential direction defined by a recording start position by the image forming unit and a transfer position by the transfer unit. Along the first and second peripheral surfaces, and each of the first and second peripheral surfaces has a recording area along the circumferential direction at least an integral multiple of the length of the sheet. An image forming apparatus comprising: 2. An image formation for a plurality of sheets of paper is performed using a recording area of at least one of the first and second peripheral surfaces, and the image formation for the plurality of sheets is completed. A first control unit controls the image forming unit and the transfer unit so that the plurality of images are transferred to the sheet.
2. The image forming apparatus according to claim 1, further comprising a control unit. 3. A second control unit for controlling the image forming unit and the transfer unit so that the image forming unit and the transfer unit perform the image forming operation and the transfer unit alternately and repeatedly so that the image forming operation and the transfer operation do not overlap. The image forming apparatus according to claim 1, further comprising a control unit. 4. The image forming apparatus according to claim 1, wherein the rotating body is formed in an endless belt shape.