What is claimed is:
1. An image forming apparatus comprising:
an image carrier which carries an electrostatic image;
developing means for developing the electrostatic image using toner;
a rotating transfer member which transfers a toner image on said image bearer;
charging means for charging an image bearer on which residual toner is deposited due to transfer by said rotating transfer member, the charging means allowing residual toner on the image bearer to be collected; and
returning means for returning toner in said charging means to said image bearer,
said rotating transfer member transferring onto said rotating transfer member at least a portion of toner returned to said image bearer by said returning means.
2. The image forming apparatus according to claim 1, wherein said developing means allows toner on said image bearer to be collected, and toner which is returned to said image bearer by said returning means but cannot be collected by said developing means is transferred onto said rotating transfer member.
3. The image forming apparatus according to claim 1, wherein said developing means allows toner on said image bearer to be collected, and toner which is returned by said returning means is not substantially collected.
4. The image forming apparatus according to claim 3, wherein said developing means has a toner carrier which feeds toner to said image bearer and collects toner from said image bearer, and the toner carrier stops rotating when returned toner passes a developing portion.
5. The image forming apparatus according to claim 1, wherein said rotating transfer member bears and conveys recording material.
6. The image forming apparatus according to claim 1, wherein said rotating transfer member is an intermediate transfer member which temporarily bears a toner image before transferring the toner image onto recording material.
7. The image forming apparatus according to claim 1, wherein different transfer currents run when said rotating transfer member transfers a toner image and when said rotating transfer member transfers toner returned by said returning means.
8. The image forming apparatus according to claim 7, wherein a smaller current runs when the returned toner is transferred than when the toner image is transferred.
9. The image forming apparatus according to claim 1, wherein said returning means returns toner to a region on said image bearer where no image is formed.
10. The image forming apparatus according to claim 9, wherein said returning means applies to charging means a voltage which differs form one which is applied to the means when an image is formed.
11. The image forming apparatus according to claim 10, wherein a vibration voltage is applied to said charging means when an image is formed, and the return voltage has a vibration component which is smaller than when an image is formed.
12. The image forming apparatus according to claim 10, wherein a vibration voltage is applied to said charging means when an image is formed, and the return voltage is a DC voltage.
13. The image forming apparatus according to claim 1, wherein said charging means has a brush which rubs said image bearer.
14. The image forming apparatus according to claim 13, wherein the brush is a magnetic brush made of magnetic particles.
15. The image forming apparatus according to claim 1, wherein the apparatus has a cleaning member which cleans the said rotating transfer member.
16. An image forming apparatus comprising:
first and second image forming stations, said first and second image forming stations both including an image carrier which carries an electrostatic image, charging means for collecting residual toner on said image bearer and charging said image bearer, developing means for developing the toner image on the image bearer using toner, and returning means for returning toner in the said charging means to said image bearer;
a rotating transfer member which superposes and transfers toner images on the image bearers of the first and second image forming stations, said rotating transfer member transferring at least part of toner returned from the charging means to said image bearers; and
controlling means for controlling the timing of toner return by the returning means of the first image forming station and that of the second image forming station so that toner returned from the first image forming station and toner returned from the second image forming station differ in position on said rotating transfer member.
17. The image forming apparatus according to claim 16, wherein said developing means allows toner on said image bearer to be collected, and toner which is returned to said image bearer by said returning means but cannot be collected by said developing means is transferred onto said rotating transfer member.
18. The image forming apparatus according to claim 16, wherein said developing means allows toner on said image bearer to be collected, and toner which is returned by said returning means is not substantially collected.
19. The image forming apparatus according to claim 18, wherein said developing means has a toner carrier which feeds toner to said image bearer and collects toner from said image bearer, and the toner carrier stops rotating when returned toner passes a developing portion.
20. The image forming apparatus according to claim 16, wherein said rotating transfer member bears and conveys recording material.
21. The image forming apparatus according to claim 16, wherein said rotating transfer member is an intermediate transfer member which temporarily bears a toner image before transferring the toner image onto recording material.
22. The image forming apparatus according to claim 21, wherein different transfer currents run when said rotating transfer member transfers a toner image and when said rotating transfer member transfers toner returned by said returning means.
23. The image forming apparatus according to claim 22, wherein a smaller current runs when the returned toner is transferred than when the toner image is transferred.
24. The image forming apparatus according to claim 16, wherein said returning means returns toner to a region on said image bearer where no image is formed.
25. The image forming apparatus according to claim 24, wherein said returning means applies to charging means a voltage which differs form one which is applied to the means when an image is formed.
26. The image forming apparatus according to claim 25, wherein a vibration voltage is applied to said charging means, and the return voltage has a vibration component which is smaller than when an image is formed.
27. The image forming apparatus according to claim 25, wherein a vibration voltage is applied to said charging means when an image is formed, and the return voltage is a DC voltage.
28. The image forming apparatus according to claim 16, wherein said charging means has a brush which rubs said image bearer.
29. The image forming apparatus according to claim 28, wherein the brush is a magnetic brush made of magnetic particles.
30. The image forming apparatus according to claim 16, wherein the apparatus has a cleaning member which cleans the said rotating transfer member.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A molding die comprising:
a commonly formed general portion; and
an exclusive portion forming a cavity,
wherein the exclusive portion is automatically attached to and detached from the general portion mounted to a molding machine by an attaching and detaching mechanism.
2. A molding die as claimed in claim 1, wherein each of a fixed die and a movable die fits an insert corresponding to the exclusive portion to a recess portion provided in a main die corresponding to the general portion, and the attaching and detaching mechanism is arranged between a bottom portion of the recess portion in the main die and a back surface portion of the insert.
3. A molding die as claimed in claim 2, wherein the attaching and detaching mechanism is constituted by a clamp apparatus which engages and inserts a T-shaped damper extended from each main die into a T-shaped slot provided in a back surface portion of the corresponding insert so as to clamp the insert within the recess portion of the main die.
4. A molding die as claimed in claim 2 or 3, wherein at least the recess portion of the main die and a portion of the insert part that is fitted to the recess portion are formed in a rectangular shape, a wedge member is floatably arranged along two adjacent wall surfaces within the recess portion of the main die in a fitting direction, a taper surface formed on a side surface of the insert is wedged to the wedge member, and remaining two surfaces of the insert are closely contacted with remaining two wall surfaces within the recess portion.
5. A molding die as claimed in claim 2 or 3, wherein at least the insert on the movable die side is provided with pressing guide means which elastically contacts the wall surface of the recess portion in the corresponding main die.
6. A molding die as claimed in any one of claims 2 to 5, wherein a high hardness material is arranged on a portion, where galling is easily generated, of an inner wall surface of the recess portion in the main die.
7. A molding die as claimed in any one of claims 2 to 6, wherein in case of including a pressing means for knocking out a molded product, the pressing means is constituted by a pressing rod corresponding to the general portion and a pressing plate, on which a pressing pin stands erect, corresponding to the exclusive portion, the pressing rod is arranged so as to penetrate the main die on the movable die side, and the pressing plate is arranged between the insert and the main die on the movable die side.
8. A molding die as claimed in claim 7, wherein a pressing means attaching and detaching mechanism is constituted by a ball lock mechanism, and the ball lock mechanism has a built-in actuator.
9. A molding die as claimed in any one of claims 1 to 8, wherein in case of including a slide which moves in a direction intersecting a die clamping direction, the slide is constituted by a slide holder corresponding to the general portion and a slide core corresponding to the exclusive portion.
10. A molding die as claimed in claim 9, wherein a slide attaching and detaching mechanism is constituted by a floating type clamp apparatus which connects the slide core and the slide holder in a floatable manner.
11. A molding die as claimed in claim 10, wherein the floating type clamp apparatus is provided with a T-shaped slot which is provided in the slide core, a T-shaped damper which is provided in the slide holder and has a leading end portion engageable with the T-shaped slot, and an actuator which makes the T-shaped damper linearly move and rotate around an axis so as to engage and disengage the leading end portion with respect to the T-shaped slot.
12. A molding die as claimed in claim 11, wherein the actuator commonly uses a slide driving cylinder.
13. A molding die as claimed in any one of claims 10 to 12, further comprising a sub clamp apparatus which enables and disables a rigid connection between the slide core and the slide holder.
14. A molding die as claimed in any one of claims 9 to 12, wherein the slide core is provided with a stopper means which is engaged with an other exclusive portion so as to regulate an insertion position of the slide core.
15. A molding die as claimed in claim 9, wherein the slide attaching and detaching mechanism is constituted by a rigid connection type clamp apparatus which rigidly connects the slide core and the slide holder.
16. A molding die as claimed in claim 15, wherein the rigid connection type clamp apparatus is provided with an engaged member which is provided in the slide core, an engagement member which is provided in the slide holder so as to be freely engaged and disengaged with respect to the engaged member, and an actuator which is provided in the slide holder and engages and disengages the engagement member with respect to the engaged member.
17. A molding die as claimed in claim 16, wherein the engaged member commonly serves as a stopper which is engaged with the other exclusive portion so as to regulate an insertion position of the slide core.
18. A molding die as claimed in any one of claims 1 to 17, wherein in case that a cooling water passage is provided in the exclusive portion, a pipe joint which communicates the cooling water passage with a water passage within the general portion or shuts off the communication in correspondence to the attachment and detachment of the exclusive portion with respect to the general portion is arranged between the general portion and the exclusive portion.
19. A molding die as claimed in any one of claims 1 to 18, wherein in case that the exclusive portion includes a core pin, an elastic ring which is frictionally in contact with the core pin so as to restrict the core pin from coming off is attached to an inner surface of an insertion hole of the core pin provided in the exclusive portion.
20. A molding die as claimed in any one of claims 1 to 18, wherein in case that the exclusive portion includes a pressurizing pin, a cylinder for driving the pressurizing pin is embedded in the exclusive portion, and a pipe joint which communicates the cylinder with a fluid pressure source or shuts off the communication in correspondence to the attachment and detachment of the exclusive portion with respect to the general portion is arranged between the exclusive portion and the general portion.
21. A molding die as claimed in claim 20, wherein the general portion is provided with a sensor which detects a detection rod interlocking with the piston within a fluid pressure cylinder so as to detect a retraction end of the pressurizing pin.
22. A molding die as claimed in any one of claims 1 to 21, wherein a connection mechanism for automatically integrating the exclusive portions in a die close state is provided between the exclusive portions.
23. A die changing method of a molding die comprising the steps of:
leaving a commonly formed general portion in a molding machine; and
automatically attaching and detaching a whole or a part of an exclusive portion forming a cavity with respect to the general portion.
24. A die changing method of a molding die as claimed in claim 23, wherein die changing is performed by integrating the exclusive portions in a die close state.
25. A die changing method of a molding die as claimed in claim 24, wherein the used exclusive portions are integrated with each other to be removed from the general portion by utilizing a die opening and closing motion of the molding machine, a new exclusive portion which is previously integrated outside the molding machine is carried in the molding machine, each exclusive portion is attached to the general portion by utilizing the die opening and closing motion, and the connection between the exclusive portions is automatically cancelled.