JPS59140466A - Image forming method of transfer system - Google Patents

Abstract

PURPOSE:To form an image forming device which is made as high in speed as possible by controlling the drive of a means for feeding off paper and a register roller for a paper feed section at the lapse point of the time corresponding to each pulse number obtd. by calculating the clock pulse synchronized with the plane moving speed of an image carrying body by an arithmetic circuit with the point of the time when the formation of an image on the image carrying body is started as a base point. CONSTITUTION:A means 40 which generates the clock pulse T synchronized with the plane moving speed of an image carrying body outputs the clock pulse T synchronized with the plane moving speed of the image carrying body 3 and inputs the same to an arithmetic circuit 41. V2, V1, l1, l2, l4 are the conditions to be determined in the stage of designing the copying machine and are set preliminarily as arithmetic constants in the circuit 41. A means 35 for feeding off paper for a paper feed section and a means 42 for controlling the drive of a register roller 32 turn on and off a clutch which turns on and off the rotation of the means for feeding off paper or a means CL1 for attaching, detaching and oscillating said means to and from the paper plane of the paper feed section and a clutch CL2 which turns on and off the rotation of the roller 32 at the point determined by the equations.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention forms an image on the surface of an image carrier driven by surface movement,
A transfer method image in which a single sheet of paper is edged out from a paper feeding unit by a paper feeding means to an image transfer position, and is fed through a register roller for image positioning, and the image on the image carrier surface is sequentially transferred to the paper surface. Regarding the forming device, it is assumed that paper feeding from the paper feed section is carried out at a relatively low speed that ensures reliable and stable sequential feeding of single sheets, while the overall image forming speed of the device is made as fast as possible. The purpose of the present invention is to provide an image forming apparatus.

FIG. 1 is a sectional view showing a schematic configuration of an example of a transfer type electronic copying machine as a specific example of a transfer type image forming apparatus. When the original M is placed on the original crow 1 and the desired magnification m is set using the copy magnification selector on the copier operation panel (not shown), the zoom lens 2 shifts in one of the directions shown by the arrow A. do. At this time, the optical path length between the zoom lens 2 and the document M, that is, the optical path length on the object world side, is set to 171. The optical path length between the zoom lens 2 and the position of the rod end of the drum filter is 9, that is, the optical path length on the image field side.

Then, there is a relationship of Li /Ll = m, and the shift amount of the zoom lens is (Ll - Lt)/2. The period distance is 1 / f = 1 / : Ll + 1 / Lt
= 1/Ll + 1/mIl.

You can zoom in as in the relationship.

Next, use the copy material selector (not shown) to select the type of copy material (size, paper, etc.) to be used, select other conditions such as the number of copies, image placement, etc., and press the copy start button ( (not shown), the electrophotographic photosensitive drum 6 starts rotating clockwise in the drawing.

Next, in order to scan the original, the first mirror 4, which is the active part of the optical system, rotates the second mirror 5 and the sixth mirror 6 toward the right in the figure at a speed of 1/ry+ times the circumferential speed of the photosensitive drum 6. begin to move in the same direction at a speed 1/2 m times the circumferential speed of the drum. The original image is captured by the first mirror 4 degrees and the second mirror 5 degrees. An image is formed on the photosensitive drum 6 at the image forming section 8 by an optical projection means consisting of a third mirror 6, a zoom lens 2, and a fourth mirror 7. The surface of the rotating photosensitive drum 6 is charged by a charger 9, which is a pre-processing device, before the imaging unit 8, and then passes through the imaging unit 8 and is charged by sequentially receiving the slit fog light of the original image. An electrolytic latent image is formed and then passes through a developing device 11, whereby the latent image is sequentially developed. Next, the copying materials 16 to 19 sent from the selected cassette of the paper feed section cassettes 12 to 15 are brought into close contact with the photosensitive drum B on the microscope screen, and the transfer charger 20 transfers the visible images on the photosensitive drum to the copying material. transcribed. After the transfer, the copy material is separated from the photosensitive drum by a separation static eliminator 21, guided to a conveyor belt 22, and transferred to a fixing device 2.
6 and discharge row 224, and is stored in the tray 25. On the other hand, the photosensitive drum 6 is cleaned of residual toner after transfer by the cleaner 26, and the next cycle is repeated again.

In addition, 27 is a front static eliminator, and 28 is a power transformer.

29 is a main body drive motor, 30 is a suction fan for conveying the copy material, and 61 is a first mirror 4 and a second mirror 4 in relative synchronization with the circumferential speed of the photosensitive drum. A DCC thermomotor drives and scans the fifth mirror 5.6, 32- is a register roller, and 3. Reference numeral 4 denotes a relay conveyance roller, and 35 to 38 denote paper feed rollers that feed copying materials one by one from the paper feed section cassettes 12 to 15.

The register roller 62 moves the selected paper feed section cassette 12'
After the leading edge of the copying material 16 to 19 fed out one sheet by the paper feed rollers 5 to 68 from the paper feeding rollers 5 to 15 is temporarily stopped, when the leading edge of the developed image on the surface of the photosensitive drum 3 reaches the transfer unit 20, the copying material The leading end portion of the drum 3 is also conveyed again at the same time as the peripheral speed of the drum roller at the timing of reaching the transfer section 20, and synchronously aligns the image surface of the drum 3 with the surface of the copying material.

By the way, there is a strong demand for image forming apparatuses such as copying machines to be as fast as possible, and for this reason, there is a need to increase the speed of the image forming process on the drum 3, which is the image carrier, and the speed of feeding each sheet of paper from the paper feed section. Equipment design is adopted.

However, even though the speed of the image forming process on the carrier increases, the speed at which each sheet of paper is fed from the paper feed section increases as the rotational speed of the paper feed rollers 65 to 68 increases. Slip may easily occur between the roller and the paper surface.

The reliability and reliability of single-sheet feeding is reduced, for example, because multiple sheets of paper are easily conveyed at one time, such as broken or double-feeding.

Therefore, the paper is fed from the paper feed unit at a relatively low speed that ensures reliable single-sheet feeding, and the execution speed of other image forming processes is increased, and the speed difference between the two can be rationalized. It is desirable to increase the overall image forming speed by arranging them in a similar manner. The present invention realizes this with a simple configuration.

It is something that

That is, the present invention will be explained based on FIG. 2, which is a further simplified model of the copying machine shown in FIG.
Forms an image on the surface and transfers it to the image transfer position 20 at the paper feed section 12 (13 to
15) to the paper feeding means 35 (36 to 38).
) Register roller 6 for aligning the sheet 16 (17 to 19) fed out one sheet with the forming member on the side of the image carrier 6
In an image forming apparatus of a type in which the image on the image carrier surface is transferred to the paper surface by feeding the image carrier via the image carrier 2, means for detecting the start time of image formation on the image carrier 3; and means for detecting the paper size used; A means 40 for generating a clock pulse T synchronized with the surface movement speed of the image carrier, an arithmetic circuit 41 whose arithmetic elements are information a to j below, and the performance of the circuit.

According to the result, the paper feed unit 35 (!'+6
~38) and a control means 42 for controlling the drive of the register roller 32, and the arithmetic circuit 41 performs A,
(1-r tt 1B-t4) /Co 1L
/C0B, (tt-Lx-As-14)/C
O1L/Co +ts /C+C1(tx t-t
)/C.

D, (tl lv)/Co1L/shi.

The number of clock pulses is calculated, and the control means 42 controls the paper feeding section paper feeding means 65 at a time point corresponding to each number of pulses of A-B-CD based on the starting point of image formation on the image carrier 6. The paper feeding operation (36 to 38) is started and stopped, and the drive of the register row 232 is started and stopped. The gist of the present invention is a transfer type image forming apparatus characterized by the following.

a, surface movement speed of image carrier 6 and register roller 62
Paper transport speed...■.

b. Paper feeding speed of paper feeding unit 35 (36 to 58)...V.

C, clock pulse frequency...P (Hz) d, distance along the surface of the image carrier 6 from the image formation start position 8 of the image carrier to the image transfer position 20 degrees...t.

e. Length of paper conveyance path from register roller 62 to image transfer position 20...t.

f, Set paper 16 (17) in paper feed section 12 (13-15)
~19) Paper conveyance path length from the leading edge position to the register roller 32...t.

V, paper feeding means 35 (3'1 to 38) of the paper feeding section
Distance from the position to the leading edge of the set paper 16 (17 to 19)...t4 h, dimension of the paper used in the paper transport direction...Li, amount of movement of the image carrier surface per 1 clock pulse, and 1 clock pulse Amount of paper conveyed by the register roller 32 per hit...
Co (=V6/P)j, paper conveyance amount by the paper feeding section paper feeding means 35 (36 to 38) per clock pulse...C, (=V1/P) However, in the above, v0≧ Let v,,L>t.

In the above, the means for detecting the start point of image formation on the image carrier 3 is omitted from the figure; however, in the case of a copying machine with a moving optical system, such as the example shown in FIG. A sensor such as a micro switch or a constant current switch detects that the moved first mirror 4 has moved to the document scanning start point,
The detection signal may be inputted as the image formation start signal S to the arithmetic circuit 41 or the control circuit 42.

The used paper size detection means is equipped with multistage paper feed sections 12 to 15 like the copying machine shown in FIG. In some cases, a copy material selector specifies the size of the paper to be used, and the copy material selector itself is a means for detecting the paper size to be used.

When the paper size to be used is specified, the paper feed unit containing the paper of that size is designated to operate, and the paper size information to be used, that is, the dimension of the paper to be used in the paper conveyance direction is automatically set as a calculation element in the calculation circuit 41. be done. In addition, if a cassette containing paper of the used size is installed in the copier machine each time the paper size is changed, when a cassette containing paper of the used size is installed, the cassette will be compatible with that cassette. When the switch on the machine side is pressed, the paper size information to be used, that is, the size of the paper to be used in the paper transport direction is automatically set in the arithmetic circuit 41.

The means 40 for generating clock pulses T synchronized with the surface movement speed of the image carrier 2 includes a disk 40a having a number of teeth or small holes formed at equal intervals around the periphery thereof, which is integrated with the rotating shaft of the image carrier 3. Mounted and rotated, or rotated in conjunction with the image carrier 6, the photoelectric unit (photoelectric unit) 40 is formed by the teeth or small holes of the disk 40a.
By intermittently opening and closing the optical path b, the photoelectric unit 40b outputs a clock pulse T synchronized with the surface movement speed of the image carrier 6, and inputs it to the arithmetic circuit 41.

■.・■, ・tl・t, and ・t4 are conditions determined at the time of designing the copying machine, and these are set in advance as calculation constants in the calculation circuit 41.

Co, C, are Vo/P, V, respectively in the arithmetic circuit 41.
/P is calculated.

t is different for each paper feed section in an apparatus having multiple paper feed sections 12 to 15 as in the example shown in FIG. When a section is designated to be activated, t corresponding to that sheet feeding section is set in the arithmetic circuit 41 as an arithmetic element.

If the copying machine has one cassette loading slot and a cassette containing paper of the size to be used is loaded each time the paper size is changed, a constant value common to each replacement cassette is set. Therefore, the above v0・V,・t,・t
, t4, the means 42 for controlling the driving of the paper feeding unit 35 ('') 6 to 8) and the register roller 62, which is set as a calculation constant in the calculation circuit 41 in advance, is the paper feeding unit. A circuit that gives an on/off signal to a clutch CL1 that turns on and off the rotation of the register roller 62, or a means CL1 that swings the means toward and away from the paper surface of the paper feeding section, and a clutch CL2 that turns on and off the rotation of the register roller 62. It is.

Although specific circuits for the arithmetic circuit 41 and the control means circuit 42 are omitted, suitable circuits can be easily constructed.

Figure 3 shows V. :V, = 2:1 is set, the paper feeding means 35 (36 to 68) of the paper feeding section.

and on/off timing chart of the register roller 62.

If the paper feed units 12 to 15 and the register rollers 32 are controlled in relation to each other as described above, paper feed from the paper feed units 12 to 15 is set to a relatively low speed that can ensure stable and reliable paper feeding. However, the paper is subsequently conveyed by the timing roller 32, which rotates at a high speed corresponding to the process execution speed of the image forming section, which is set to a high speed, with virtually no loss time and is conveyed in a well-timed manner to the image forming section (transfer section 2).
0), it is possible to construct an image forming apparatus in which single sheet feeding from the sheet feeding section is stable and high-speed copying is possible overall.

Furthermore, no inconvenience occurs due to differences in paper size or copying magnification. The above calculation pulse value may be set to a value with a slight margin α taken into consideration such as time delay of the clutch, slippage between the roller and the copy paper, etc., and this is also within the scope of the present invention. Roller 35 (36~
Control is also possible by providing a paper presence/absence sensor between the register roller 2 and the register roller 2; It is not as effective as the conventional method, and there are problems in terms of sensor cost and reliability. In addition, if the distance between the paper feed rollers 35 (36 to 68 and the register rollers 62 is longer than the length of the paper used), that is, q <
In the case of ts, a relay conveyance roller is disposed midway between the paper feed roller 35 (36 to 38) and the register roller 32. A means for detecting the presence or absence of paper is also provided.

The rotation of the paper feed roller 35 (36 to 68) is stopped when the leading edge of the paper fed out by the roller reaches the register roller 3.
2. Alternatively, it may be at any time from the time the paper is gripped by the intermediate conveyance roller until the trailing edge of the paper leaves the paper feed roller section, and the paper is still under the roller when the paper feed roller stops driving. After passing through the paper, the paper continues to be transported by the rotational force of the register roller or the intermediate transport roller, and during this time the paper feed roller rotates idly and does not interfere with the paper transport.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an example of a transfer type image forming apparatus;
Fig. 2 is a control system diagram, and Fig. 6 is a timing chart. 3 is a rotating photosensitive drum, 20 is a transfer device, 12 to 15 are multistage paper feeding units, and 35 to 38 are paper feeding rollers. 32 is Timinda Lola.

Claims (1)

[Claims] (1) An image is formed on the surface of an image carrier driven by surface movement. The image on the image carrier surface is transferred to the image transfer position by feeding a sheet of paper fed out one sheet from the paper feeding section by the paper feeding means through the register row 2 for alignment with the formed image on the image carrier surface side. In an image forming apparatus that transfers images onto a paper surface, the image forming apparatus includes a means for detecting the start point of image formation on an image carrier, a means for detecting the paper size used, and a clock pulse that is synchronized with the surface movement speed of the image carrier. means, an arithmetic circuit having the following information a to j as arithmetic elements, and a control B for controlling the driving of the paper feeding means and register rollers of the paper feeding unit according to the arithmetic results of the circuit, (tt At -As 7
4)/Co+L/Co+ta/CsC, (tt i
t)/C. The number of clock pulses D, <11-At)/Co+L/C0 is calculated, and the Σ time elapsed point corresponding to each number of pulses A-B-C-D is calculated based on the starting point of image formation on the image carrier. Then, the control means causes the sheet feeding section sheet feeding means to start and stop the sheet feeding operation, and to start and stop the driving of the register rollers. A transfer type image forming apparatus characterized by the following. Note a, surface movement speed of the image carrier, and paper conveyance speed of the register roller...■. b. Paper feeding speed of the paper feeding unit paper feeding unit...
■. C, clock pulse frequency...P (Hz)d, distance along the image carrier surface from the image formation start position of the image carrier to the image transfer position...t. e. Paper conveyance path length from the register roller to the image transfer position 1t...t. f, paper transport path length from the leading edge position of the set paper in the paper feed unit to the register roller...t. t, distance from the paper feed unit position of the paper feeding unit to the leading edge of the set paper...t4 h, dimension of the paper used in the paper transport direction...Li, amount of movement of the image carrier surface per one clock pulse, and Amount of paper conveyed by the register roller per pulse...Co
(=Vo/P)jl Amount of paper conveyed by the paper feeding unit paper feeding means per clock pulse...CI
(=Vt/p) However, in the above, ■. ≧v,, h>z
Set it to 3.